drm/debugfs: bridges_show: show refcount

Now that bridges are refcounted, exposing the refcount in debugfs can be
useful.

Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250819-drm-bridge-debugfs-removed-v7-1-970702579978@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Author: lucaceresoli

drivers/gpu/drm/drm_bridge.c

@@ -1435,6 +1435,9 @@ static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
 					   unsigned int idx)
 {
 	drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs);
+
+	drm_printf(p, "\trefcount: %u\n", kref_read(&bridge->refcount));
+
 	drm_printf(p, "\ttype: [%d] %s\n",
 		   bridge->type,
 		   drm_get_connector_type_name(bridge->type));