[PATCH] PPC32: Select arch/ppc/kernel/head.S on CONFIG_PPC_STD_MMU.

From: Tom Rini <trini@kernel.crashing.org>

PPC32: Select arch/ppc/kernel/head.S on CONFIG_PPC_STD_MMU.

- Don't pick a head*.S by default, instead select head.S on
  CONFIG_PPC_STD_MMU.  This is more consistent with how we
  case things in this file.

arch/ppc/kernel/Makefile

@@ -9,8 +9,7 @@ ifdef CONFIG_4xx
 EXTRA_AFLAGS		:= -Wa,-m405
 endif
 
-# Start off with 'head.o', change as needed.
-extra-y				:= head.o
+extra-$(CONFIG_PPC_STD_MMU)	:= head.o
 extra-$(CONFIG_40x)		:= head_4xx.o
 extra-$(CONFIG_44x)		:= head_44x.o
 extra-$(CONFIG_8xx)		:= head_8xx.o