drm/i915/glk: Enable pipe CSC

Now that the pre-csc degamma table is set up correctly in Geminilake,
pipe CSC can be enabled without causing a black screen.

v2: Rebase.
Signed-off-by: NAnder Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170217120630.6143-3-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -3327,6 +3327,7 @@ static void skylake_update_primary_plane(struct drm_plane *plane,
 	if (IS_GEMINILAKE(dev_priv)) {
 		I915_WRITE(PLANE_COLOR_CTL(pipe, plane_id),
 			   PLANE_COLOR_PIPE_GAMMA_ENABLE |
+			   PLANE_COLOR_PIPE_CSC_ENABLE |
 			   PLANE_COLOR_PLANE_GAMMA_DISABLE);
 	} else {
 		plane_ctl |=

drivers/gpu/drm/i915/intel_sprite.c

@@ -224,6 +224,7 @@ skl_update_plane(struct drm_plane *drm_plane,
 	if (IS_GEMINILAKE(dev_priv)) {
 		I915_WRITE(PLANE_COLOR_CTL(pipe, plane_id),
 			   PLANE_COLOR_PIPE_GAMMA_ENABLE |
+			   PLANE_COLOR_PIPE_CSC_ENABLE |
 			   PLANE_COLOR_PLANE_GAMMA_DISABLE);
 	} else {
 		plane_ctl |=