drm/tegra: plane: Support format modifiers

Pass the list of valid format modifiers to planes upon initialization
and implement the ->format_mod_supported() callback so that userspace
can query for the valid combinations of formats and modifiers.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/dc.h b/drivers/gpu/drm/tegra/dc.h
index 096a81a..d2b50d3 100644
--- a/drivers/gpu/drm/tegra/dc.h
+++ b/drivers/gpu/drm/tegra/dc.h
@@ -66,6 +66,7 @@
 	unsigned int num_primary_formats;
 	const u32 *overlay_formats;
 	unsigned int num_overlay_formats;
+	const u64 *modifiers;
 };
 
 struct tegra_dc {