drm/bridge/lontium-lt9611uxc: fix provided connector suport

- set DRM_CONNECTOR_POLL_HPD as the connector will generate hotplug
  events on its own

- do not call drm_kms_helper_hotplug_event() unless mode_config.funcs
  pointer is not NULL to remove possible kernel oops.

Fixes: bc6fa867 ("drm/bridge/lontium-lt9611uxc: move HPD notification out of IRQ handler")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708230329.395976-1-dmitry.baryshkov@linaro.org

drivers/gpu/drm/bridge/lontium-lt9611uxc.c

@@ -167,9 +167,10 @@ static void lt9611uxc_hpd_work(struct work_struct *work)
 	struct lt9611uxc *lt9611uxc = container_of(work, struct lt9611uxc, work);
 	bool connected;
 
-	if (lt9611uxc->connector.dev)
+	if (lt9611uxc->connector.dev) {
+		if (lt9611uxc->connector.dev->mode_config.funcs)
 			drm_kms_helper_hotplug_event(lt9611uxc->connector.dev);
-	else {
+	} else {
 
 		mutex_lock(&lt9611uxc->ocm_lock);
 		connected = lt9611uxc->hdmi_connected;
@@ -339,6 +340,8 @@ static int lt9611uxc_connector_init(struct drm_bridge *bridge, struct lt9611uxc
 		return -ENODEV;
 	}
 
+	lt9611uxc->connector.polled = DRM_CONNECTOR_POLL_HPD;
+
 	drm_connector_helper_add(&lt9611uxc->connector,
 				 &lt9611uxc_bridge_connector_helper_funcs);
 	ret = drm_connector_init(bridge->dev, &lt9611uxc->connector,