drm/tegra: dsi: Mark connector hotpluggable

DSI panels can always be hotplugged via the DSI bus' attach/detach
infrastructure, so unconditionally mark the connector hotpluggable.

While at it, also make sure that when a panel is detached the connector
is marked unconnected before calling into the DRM hotplug helpers to
reflect the correct state.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dsi.c

@@ -804,10 +804,10 @@ static int tegra_dsi_host_detach(struct mipi_dsi_host *host,
 	struct tegra_output *output = &dsi->output;
 
 	if (output->panel && &device->dev == output->panel->dev) {
+		output->panel = NULL;
+
 		if (output->connector.dev)
 			drm_helper_hpd_irq_event(output->connector.dev);
-
-		output->panel = NULL;
 	}
 
 	return 0;
@@ -836,6 +836,8 @@ static int tegra_dsi_probe(struct platform_device *pdev)
 	if (err < 0)
 		return err;
 
+	dsi->output.connector.polled = DRM_CONNECTOR_POLL_HPD;
+
 	/*
 	 * Assume these values by default. When a DSI peripheral driver
 	 * attaches to the DSI host, the parameters will be taken from