[ARM] nommu: trivial fixups for head-nommu.S and the Makefile

This patch fix compilation problem of start-up codes.
(head-nommu.S, arch/arm/kernel/Makefile)

Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 2ce0e3a..a601b8b 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -29,7 +29,7 @@
   obj-y		+= io.o
 endif
 
-head-y			:= head.o
+head-y			:= head$(MMUEXT).o
 obj-$(CONFIG_DEBUG_LL)	+= debug.o
 
 extra-y := $(head-y) init_task.o vmlinux.lds