ion: Reenable the build

Now that ION builds, reenable it in the build.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/Makefile

 ccflags-y += -I$(src)			# needed for trace events
 
-# ION doesn't build just yet, so disable it from the build
-#obj-y					+= ion/
+obj-y					+= ion/
 
 obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o
 obj-$(CONFIG_ASHMEM)			+= ashmem.o