drm/crtc_helper/set_config: Remove redundant NULL pointer check on set->mode

We've done sanity NULL pointer check on set->mode at the beginning of
drm_crtc_helper_set_config() and bailed out if necessary, thus any later on
check is redundant.

Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452751210-19216-2-git-send-email-gnuiyl@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc_helper.c

@@ -588,7 +588,7 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 	if (set->x != set->crtc->x || set->y != set->crtc->y)
 		fb_changed = true;
 
-	if (set->mode && !drm_mode_equal(set->mode, &set->crtc->mode)) {
+	if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
 		DRM_DEBUG_KMS("modes are different, full mode set\n");
 		drm_mode_debug_printmodeline(&set->crtc->mode);
 		drm_mode_debug_printmodeline(set->mode);