Makefile: output migration warnings to stderr

Output the device model migration warnings to stderr. This allows tools
like buildman to pick them up rather than suppressing them along with
the normal build output on stdout.
Signed-off-by: NChris Packham <judge.packham@gmail.com>

Makefile

@@ -912,47 +912,47 @@ cmd_cfgcheck = $(srctree)/scripts/check-config.sh $2 \
 
 all:		$(ALL-y) cfg
 ifeq ($(CONFIG_DM_I2C_COMPAT)$(CONFIG_SANDBOX),y)
-	@echo "===================== WARNING ======================"
-	@echo "This board uses CONFIG_DM_I2C_COMPAT. Please remove"
-	@echo "(possibly in a subsequent patch in your series)"
-	@echo "before sending patches to the mailing list."
-	@echo "===================================================="
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board uses CONFIG_DM_I2C_COMPAT. Please remove"
+	@echo >&2 "(possibly in a subsequent patch in your series)"
+	@echo >&2 "before sending patches to the mailing list."
+	@echo >&2 "===================================================="
 endif
 ifeq ($(CONFIG_MMC),y)
 ifneq ($(CONFIG_DM_MMC)$(CONFIG_OF_CONTROL)$(CONFIG_BLK),yyy)
-	@echo "===================== WARNING ======================"
-	@echo "This board does not use CONFIG_DM_MMC. Please update"
-	@echo "the board to use CONFIG_DM_MMC before the v2019.04 release."
-	@echo "Failure to update by the deadline may result in board removal."
-	@echo "See doc/driver-model/MIGRATION.txt for more info."
-	@echo "===================================================="
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board does not use CONFIG_DM_MMC. Please update"
+	@echo >&2 "the board to use CONFIG_DM_MMC before the v2019.04 release."
+	@echo >&2 "Failure to update by the deadline may result in board removal."
+	@echo >&2 "See doc/driver-model/MIGRATION.txt for more info."
+	@echo >&2 "===================================================="
 endif
 endif
 ifeq ($(CONFIG_USB),y)
 ifneq ($(CONFIG_DM_USB)$(CONFIG_OF_CONTROL)$(CONFIG_BLK),yyy)
-	@echo "===================== WARNING ======================"
-	@echo "This board does not use CONFIG_DM_USB. Please update"
-	@echo "the board to use CONFIG_DM_USB before the v2019.07 release."
-	@echo "Failure to update by the deadline may result in board removal."
-	@echo "See doc/driver-model/MIGRATION.txt for more info."
-	@echo "===================================================="
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board does not use CONFIG_DM_USB. Please update"
+	@echo >&2 "the board to use CONFIG_DM_USB before the v2019.07 release."
+	@echo >&2 "Failure to update by the deadline may result in board removal."
+	@echo >&2 "See doc/driver-model/MIGRATION.txt for more info."
+	@echo >&2 "===================================================="
 endif
 endif
 ifeq ($(CONFIG_LIBATA)$(CONFIG_DM_SCSI)$(CONFIG_MVSATA_IDE),y)
-	@echo "===================== WARNING ======================"
-	@echo "This board does not use CONFIG_DM_SCSI. Please update"
-	@echo "the storage controller to use CONFIG_DM_SCSI before the v2019.07 release."
-	@echo "Failure to update by the deadline may result in board removal."
-	@echo "See doc/driver-model/MIGRATION.txt for more info."
-	@echo "===================================================="
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "This board does not use CONFIG_DM_SCSI. Please update"
+	@echo >&2 "the storage controller to use CONFIG_DM_SCSI before the v2019.07 release."
+	@echo >&2 "Failure to update by the deadline may result in board removal."
+	@echo >&2 "See doc/driver-model/MIGRATION.txt for more info."
+	@echo >&2 "===================================================="
 endif
 ifeq ($(CONFIG_OF_EMBED),y)
-	@echo "===================== WARNING ======================"
-	@echo "CONFIG_OF_EMBED is enabled. This option should only"
-	@echo "be used for debugging purposes. Please use"
-	@echo "CONFIG_OF_SEPARATE for boards in mainline."
-	@echo "See doc/README.fdt-control for more info."
-	@echo "===================================================="
+	@echo >&2 "===================== WARNING ======================"
+	@echo >&2 "CONFIG_OF_EMBED is enabled. This option should only"
+	@echo >&2 "be used for debugging purposes. Please use"
+	@echo >&2 "CONFIG_OF_SEPARATE for boards in mainline."
+	@echo >&2 "See doc/README.fdt-control for more info."
+	@echo >&2 "===================================================="
 endif
 	@# Check that this build does not use CONFIG options that we do not
 	@# know about unless they are in Kconfig. All the existing CONFIG