ARM: tegra: combine duplicate Makefile rules

The rules to generate u-boot-{no,}dtb-tegra.bin were almost identical.
Combine them into a single paremeterized rule. This will allow the next
patch to edit a single rule, rather than being cut/paste twice.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NSimon Glass <sjg@chromium.org>
Signed-off-by: NTom Warren <twarren@nvidia.com>

Makefile

@@ -515,17 +515,18 @@ $(obj)u-boot.spr:	$(obj)u-boot.img $(obj)spl/u-boot-spl.bin
 
 ifeq ($(SOC),tegra20)
 ifeq ($(CONFIG_OF_SEPARATE),y)
-$(obj)u-boot-dtb-tegra.bin:	$(obj)spl/u-boot-spl.bin $(obj)u-boot.bin $(obj)u-boot.dtb
-		$(OBJCOPY) ${OBJCFLAGS} --pad-to=$(CONFIG_SYS_TEXT_BASE) -O binary $(obj)spl/u-boot-spl $(obj)spl/u-boot-spl-pad.bin
-		cat $(obj)spl/u-boot-spl-pad.bin $(obj)u-boot.bin $(obj)u-boot.dtb > $@
-		rm $(obj)spl/u-boot-spl-pad.bin
+nodtb=dtb
+dtbfile=$(obj)u-boot.dtb
 else
-$(obj)u-boot-nodtb-tegra.bin:	$(obj)spl/u-boot-spl.bin $(obj)u-boot.bin
+nodtb=nodtb
+dtbfile=
+endif
+
+$(obj)u-boot-$(nodtb)-tegra.bin: $(obj)spl/u-boot-spl.bin $(obj)u-boot.bin $(dtbfile)
 		$(OBJCOPY) ${OBJCFLAGS} --pad-to=$(CONFIG_SYS_TEXT_BASE) -O binary $(obj)spl/u-boot-spl $(obj)spl/u-boot-spl-pad.bin
-		cat $(obj)spl/u-boot-spl-pad.bin $(obj)u-boot.bin > $@
+		cat $(obj)spl/u-boot-spl-pad.bin $(obj)u-boot.bin $(dtbfile) > $@
 		rm $(obj)spl/u-boot-spl-pad.bin
 endif
-endif
 
 ifeq ($(CONFIG_SANDBOX),y)
 GEN_UBOOT = \