drm/i915/skl: Adjust assert_sprites_disabled()

Let's put to good use the new PLANE_CTL macros.
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -1335,7 +1335,14 @@ static void assert_sprites_disabled(struct drm_i915_private *dev_priv,
 	int reg, sprite;
 	u32 val;
 
-	if (IS_VALLEYVIEW(dev)) {
+	if (INTEL_INFO(dev)->gen >= 9) {
+		for_each_sprite(pipe, sprite) {
+			val = I915_READ(PLANE_CTL(pipe, sprite));
+			WARN(val & PLANE_CTL_ENABLE,
+			     "plane %d assertion failure, should be off on pipe %c but is still active\n",
+			     sprite, pipe_name(pipe));
+		}
+	} else if (IS_VALLEYVIEW(dev)) {
 		for_each_sprite(pipe, sprite) {
 			reg = SPCNTR(pipe, sprite);
 			val = I915_READ(reg);