[PATCH] [V2]powerpc/dts: fix not include DTC_FLAGS

[Youlin Song]

A central rule exists to create `$(obj)/%.dtb` from
`$(src)/%.dts`,DTC_FLAGS flag must be used with it.
See other architecture and Documentation:
arch/microblaze/boot/dts/Makefile
Documentation/kbuild/makefiles.rst +1433

Signed-off-by: Youlin Song <syl.loop at gmail.com>
---
 arch/powerpc/boot/Makefile     | 2 --
 arch/powerpc/boot/dts/Makefile | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 2b8da923ceca..a3bc3aec3c0c 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -72,8 +72,6 @@ endif
 
 BOOTCFLAGS	+= -I$(objtree)/$(obj) -I$(srctree)/$(obj)
 
-DTC_FLAGS	?= -p 1024
-
 $(obj)/4xx.o: BOOTCFLAGS += -mcpu=405
 $(obj)/ebony.o: BOOTCFLAGS += -mcpu=440
 $(obj)/cuboot-hotfoot.o: BOOTCFLAGS += -mcpu=405
diff --git a/arch/powerpc/boot/dts/Makefile b/arch/powerpc/boot/dts/Makefile
index fb335d05aae8..c21165c0cd76 100644
--- a/arch/powerpc/boot/dts/Makefile
+++ b/arch/powerpc/boot/dts/Makefile
@@ -2,5 +2,6 @@
 
 subdir-y += fsl
 
+DTC_FLAGS   ?= -p 1024
 dtstree		:= $(srctree)/$(src)
 dtb-$(CONFIG_OF_ALL_DTBS) := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts))
-- 
2.25.1