gpu: ion: Add ION Memory Manager

Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index a290be5..65b07f4 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -23,6 +23,8 @@
 
 source "drivers/gpu/stub/Kconfig"
 
+source "drivers/gpu/ion/Kconfig"
+
 config VGASTATE
        tristate
        default n