drm/fb helper: don't call drm_crtc_helper_set_config

Go through the interface vtable instead, because not everyone might be
using the crtc helper code.

Cc: dri-devel@lists.freedesktop.org
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_fb_helper.c

@@ -228,7 +228,7 @@ bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
 	int i, ret;
 	for (i = 0; i < fb_helper->crtc_count; i++) {
 		struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
-		ret = drm_crtc_helper_set_config(mode_set);
+		ret = mode_set->crtc->funcs->set_config(mode_set);
 		if (ret)
 			error = true;
 	}