disp: msm: dp: fix modeset locking in dp_mst_connector_detect

The modeset lock acquired in dp_mst_connector_detect is not
being released after the detection is completed, which
causes subsequent deadlock.

Added a call to drm_modeset_drop_locks when coming out of
dp_mst_connector_detect.

Change-Id: Ibce79934d0ac23fed4985291c5c6078cb982e812
Signed-off-by: Sudarsan Ramesh <sudarame@codeaurora.org>

msm/dp/dp_mst_drm.c

@@ -1380,7 +1380,9 @@ dp_mst_connector_detect(struct drm_connector *connector, bool force,
 	DP_MST_INFO("conn:%d status:%d\n", connector->base.id, status);
 	SDE_EVT32_EXTERNAL(SDE_EVTLOG_FUNC_EXIT, connector->base.id, status);
 
+	drm_modeset_drop_locks(&ctx);
 	drm_modeset_acquire_fini(&ctx);
+
 	return status;
 }