ANDROID: GKI: Add DRM_TTM config to GKI

When certain DRM drivers, such as virtio-gpu, are built out of tree,
they might depend on parts of DRM, such as DRM_TTM, that are not
included in all configs.

This CL adds the config to GKI_HACKS_TO_FIX, allowing DRM drivers that
use DRM_TTM to link successfully against GKI.

Test: Build and run virtio-gpu as an external module
Change-Id: I1ae869b7394a6059c0f3880bdc65a0b3ceb3e004
Bug: 153580313
Signed-off-by: Lingfeng Yang <lfy@google.com>
diff --git a/init/Kconfig.gki b/init/Kconfig.gki
index 3fc2d9a..a5e8f88 100644
--- a/init/Kconfig.gki
+++ b/init/Kconfig.gki
@@ -5,6 +5,7 @@
 	select DRM_GEM_CMA_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_MIPI_DSI
+	select DRM_TTM if (HAS_IOMEM && DRM)
 	select VIDEOMODE_HELPERS
 	select WANT_DEV_COREDUMP
 	help