drm/i915: Fix ILK-IVB primary plane enable delays

Primary and sprite plane enable on ILK-IVB may take two frames to complete

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103925
Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1545305168-6047-1-git-send-email-juhapekka.heikkila@gmail.com

drivers/gpu/drm/i915/intel_display.c

@@ -10851,8 +10851,11 @@ int intel_plane_atomic_calc_changes(const struct intel_crtc_state *old_crtc_stat
 	 * Despite the w/a only being listed for IVB we assume that
 	 * the ILK/SNB note has similar ramifications, hence we apply
 	 * the w/a on all three platforms.
+	 *
+	 * With experimental results seems this is needed also for primary
+	 * plane, not only sprite plane.
 	 */
-	if (plane->id == PLANE_SPRITE0 &&
+	if (plane->id != PLANE_CURSOR &&
 	    (IS_GEN_RANGE(dev_priv, 5, 6) ||
 	     IS_IVYBRIDGE(dev_priv)) &&
 	    (turn_on || (!needs_scaling(old_plane_state) &&