drm/i915: Add runtime PM's usage_count in i915_runtime_pm_status

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2490,6 +2490,8 @@ static int i915_runtime_pm_status(struct seq_file *m, void *unused)
 	seq_printf(m, "GPU idle: %s\n", yesno(!dev_priv->mm.busy));
 	seq_printf(m, "IRQs disabled: %s\n",
 		   yesno(!intel_irqs_enabled(dev_priv)));
+	seq_printf(m, "Usage count: %d\n",
+		   atomic_read(&dev->dev->power.usage_count));
 
 	return 0;
 }