ARC: [build] cleanup Makefile a bit

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index fa30453..ac14601 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -96,11 +96,12 @@
 
 libs-y		+= arch/arc/lib/ $(LIBGCC)
 
+boot		:= arch/arc/boot
+
 #default target for make without any arguements.
-KBUILD_IMAGE := bootpImage
+KBUILD_IMAGE	:= bootpImage
 
 all:	$(KBUILD_IMAGE)
-boot	:= arch/arc/boot
 
 bootpImage: vmlinux