gpu: ion: Add ION Memory Manager

Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile
index cc92778..ca2d3b3 100644
--- a/drivers/gpu/Makefile
+++ b/drivers/gpu/Makefile
@@ -1 +1 @@
-obj-y			+= drm/ vga/ stub/
+obj-y			+= drm/ vga/ stub/ ion/