drm/i915: Use drm_encoder_crtc_ok()

The intel_encoder_crtc_ok() is a duplicate of the drm_encoder_crtc_ok()
function that used to be only available in the DRM CRTC helpers. It has
recently been moved to the core, so the duplicate can now be dropped.
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/i915/intel_display.c

@@ -8493,28 +8493,6 @@ static struct drm_crtc_helper_funcs intel_helper_funcs = {
 	.load_lut = intel_crtc_load_lut,
 };
 
-static bool intel_encoder_crtc_ok(struct drm_encoder *encoder,
-				  struct drm_crtc *crtc)
-{
-	struct drm_device *dev;
-	struct drm_crtc *tmp;
-	int crtc_mask = 1;
-
-	WARN(!crtc, "checking null crtc?\n");
-
-	dev = crtc->dev;
-
-	list_for_each_entry(tmp, &dev->mode_config.crtc_list, head) {
-		if (tmp == crtc)
-			break;
-		crtc_mask <<= 1;
-	}
-
-	if (encoder->possible_crtcs & crtc_mask)
-		return true;
-	return false;
-}
-
 /**
  * intel_modeset_update_staged_output_state
  *
@@ -9679,8 +9657,8 @@ intel_modeset_stage_output_state(struct drm_device *dev,
 		}
 
 		/* Make sure the new CRTC will work with the encoder */
-		if (!intel_encoder_crtc_ok(&connector->new_encoder->base,
-					   new_crtc)) {
+		if (!drm_encoder_crtc_ok(&connector->new_encoder->base,
+					 new_crtc)) {
 			return -EINVAL;
 		}
 		connector->encoder->new_crtc = to_intel_crtc(new_crtc);