powerpc: Build little endian ppc64 kernel with ABIv2

Build the little endian ppc64 kernel with ABIv2 if the toolchain
supports it. We can identify an ABIv2 capable toolchain by the
-mabi=elfv2 compiler flag.

Signed-off-by: Anton Blanchard <anton@samba.org>
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index e8dd01a..5ba603b 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -113,9 +113,13 @@
 endif
 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)	:= -mtraceback=no
+ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
+CFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv2,-mcall-aixdesc)
+AFLAGS-$(CONFIG_PPC64)	+= $(call cc-option,-mabi=elfv2)
+else
+CFLAGS-$(CONFIG_PPC64)	+= -mcall-aixdesc
+endif
 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)