Makefile: Do not use wildcard hw/*/Kconfig as input for minikconf

The hw/*/Kconfig files should be sourced from hw/Kconfig, so there
is no need to pass them along as input files to minikconfig. We should
use the hw/*/Kconfig wildcard only for build dependencies in the Makefile.

With this change, there are now no duplicate entries in the generated
*-softmmu/config-devices.mak.d files anymore, and there is finally a
chance to get rid of stale Kconfig files like hw/bt/Kconfig, too (once
they do not show up in the config-devices.mak.d files now anymore).

Message-Id: <20200203153905.20544-1-thuth@redhat.com>
Signed-off-by: NThomas Huth <thuth@redhat.com>

Makefile

@@ -397,11 +397,11 @@ MINIKCONF_ARGS = \
     CONFIG_LINUX=$(CONFIG_LINUX) \
     CONFIG_PVRDMA=$(CONFIG_PVRDMA)
 
-MINIKCONF_INPUTS = $(SRC_PATH)/Kconfig.host $(SRC_PATH)/hw/Kconfig \
-                   $(wildcard $(SRC_PATH)/hw/*/Kconfig)
+MINIKCONF_INPUTS = $(SRC_PATH)/Kconfig.host $(SRC_PATH)/hw/Kconfig
+MINIKCONF_DEPS = $(MINIKCONF_INPUTS) $(wildcard $(SRC_PATH)/hw/*/Kconfig)
 MINIKCONF = $(PYTHON) $(SRC_PATH)/scripts/minikconf.py \
 
-$(SUBDIR_DEVICES_MAK): %/config-devices.mak: default-configs/%.mak $(MINIKCONF_INPUTS) $(BUILD_DIR)/config-host.mak
+$(SUBDIR_DEVICES_MAK): %/config-devices.mak: default-configs/%.mak $(MINIKCONF_DEPS) $(BUILD_DIR)/config-host.mak
 	$(call quiet-command, $(MINIKCONF) $(MINIKCONF_ARGS) > $@.tmp, "GEN", "$@.tmp")
 	$(call quiet-command, if test -f $@; then \
 	  if cmp -s $@.old $@; then \