[POWERPC] ppc: Use ebony_defconfig for defconfig

We used to use common_defconfig, but it was removed some time ago.

Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/ppc/Makefile b/arch/ppc/Makefile
index 8df7f0e..2352d13 100644
--- a/arch/ppc/Makefile
+++ b/arch/ppc/Makefile
@@ -43,7 +43,7 @@
 KBUILD_CFLAGS += $(cpu-as-y)
 
 # Default to the common case.
-KBUILD_DEFCONFIG := common_defconfig
+KBUILD_DEFCONFIG := ebony_defconfig
 
 head-y				:= arch/ppc/kernel/head.o
 head-$(CONFIG_8xx)		:= arch/ppc/kernel/head_8xx.o