PowerPC: merge commonly-defined flags

PLATFORM_RELFLAGS += -meabi
PLATFORM_CPPFLAGS += -ffixed-r2
were defined in all arch/powerpc/${CPU}/config.mk.

This commit moves them to arch/powerpc/config.mk.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/powerpc/config.mk b/arch/powerpc/config.mk
index e6bb935..f75c3bf 100644
--- a/arch/powerpc/config.mk
+++ b/arch/powerpc/config.mk
@@ -9,8 +9,9 @@
 
 CONFIG_STANDALONE_LOAD_ADDR ?= 0x40000
 LDFLAGS_FINAL += --gc-sections
-PLATFORM_RELFLAGS += -fpic -mrelocatable -ffunction-sections -fdata-sections
-PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__
+PLATFORM_RELFLAGS += -fpic -mrelocatable -ffunction-sections -fdata-sections \
+								-meabi
+PLATFORM_CPPFLAGS += -DCONFIG_PPC -D__powerpc__ -ffixed-r2
 PLATFORM_LDFLAGS  += -n
 
 # Support generic board on PPC