ARM: realview: fix device tree build

As it happens, two obj-$(CONFIG_FOO) += foo.o variables are
above obj-y := core.o, which doesn't work: the += directives
need to add something to the build and doesn't work if obj-y
is not set first, so move the obj-y to be on top and everything
builds nicely again.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-realview/Makefile

@@ -4,10 +4,9 @@
 ccflags-$(CONFIG_ARCH_MULTIPLATFORM) := -I$(srctree)/$(src)/include \
 	-I$(srctree)/arch/arm/plat-versatile/include
 
-
+obj-y					:= core.o
 obj-$(CONFIG_REALVIEW_DT)		+= realview-dt.o
 obj-$(CONFIG_SMP)			+= platsmp-dt.o
-obj-y					:= core.o
 
 ifdef CONFIG_ATAGS
 obj-$(CONFIG_MACH_REALVIEW_EB)		+= realview_eb.o