drm/rockchip: Remove unnecessary NULL check

The expression &private->fbdev_helper can never be NULL, so the check is
completely unnecessary.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170329144401.1804-12-thierry.reding@gmail.com

drivers/gpu/drm/rockchip/rockchip_drm_fb.c

@@ -168,10 +168,8 @@ rockchip_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 static void rockchip_drm_output_poll_changed(struct drm_device *dev)
 {
 	struct rockchip_drm_private *private = dev->dev_private;
-	struct drm_fb_helper *fb_helper = &private->fbdev_helper;
 
-	if (fb_helper)
-		drm_fb_helper_hotplug_event(fb_helper);
+	drm_fb_helper_hotplug_event(&private->fbdev_helper);
 }
 
 static void