ppc: Enable generic board support

This enables generic board support so that ppc boards can define
CONFIG_SYS_GENERIC_BOARD.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 86cf02a..59c723b 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -59,8 +59,10 @@
 
 COBJS-$(CONFIG_BAT_RW) += bat_rw.o
 ifndef CONFIG_SPL_BUILD
+ifndef CONFIG_SYS_GENERIC_BOARD
 COBJS-y	+= board.o
 endif
+endif
 COBJS-y	+= bootm.o
 COBJS-y	+= cache.o
 COBJS-y	+= extable.o