disp: msm: dsi: notify panel id during callback registration

Clients of dsi driver can register to be notified of panel id
information. Dsi is probed early during the device boot-up. If the panel
id is available with dsi driver none of the clients have registered
that early. Once clients probe and they register with the dsi driver
panel id is not passed onto clients until power on of the dsi. Change
adds support to notify the dsi clients during registration if panel id
is valid.

Change-Id: Ic475060cbec5f5b645aed865939fffe66aef071b

msm/dsi/dsi_display.c

@@ -44,6 +44,8 @@ static struct dsi_display_boot_param boot_displays[MAX_DSI_ACTIVE_DISPLAY] = {
 	{.boot_param = dsi_display_secondary},
 };
 
+static void dsi_display_panel_id_notification(struct dsi_display *display);
+
 static const struct of_device_id dsi_display_dt_match[] = {
 	{.compatible = "qcom,dsi-display"},
 	{}
@@ -2448,6 +2450,7 @@ void dsi_display_enable_event(struct drm_connector *connector,
 			display_for_each_ctrl(i, display)
 				display->ctrl[i].ctrl->panel_id_cb
 				    = *event_info;
+		dsi_display_panel_id_notification(display);
 		break;
 	default:
 		/* nothing to do */