powerpc: Don't build assembly files with ABIv2

We avoid ABIv2 when building c files since commit b2ca8c89 (powerpc:
Don't use ELFv2 ABI to build the kernel). Do the same for assembly
files.
Signed-off-by: Anton Blanchard <anton@samba.org>

arch/powerpc/Makefile

@@ -115,6 +115,7 @@ endif
 
 CFLAGS-$(CONFIG_PPC64)	:= -mtraceback=no -mcall-aixdesc
 CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv1)
+AFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv1)
 CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mcmodel=medium,-mminimal-toc)
 CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mno-pointers-to-nested-functions)
 CFLAGS-$(CONFIG_PPC32)	:= -ffixed-r2 $(MULTIPLEWORD)
@@ -151,7 +152,7 @@ endif
 CFLAGS-$(CONFIG_TUNE_CELL) += $(call cc-option,-mtune=cell)
 
 KBUILD_CPPFLAGS	+= -Iarch/$(ARCH)
-KBUILD_AFLAGS	+= -Iarch/$(ARCH)
+KBUILD_AFLAGS	+= -Iarch/$(ARCH) $(AFLAGS-y)
 KBUILD_CFLAGS	+= -msoft-float -pipe -Iarch/$(ARCH) $(CFLAGS-y)
 CPP		= $(CC) -E $(KBUILD_CFLAGS)