drm/nouveau/drm/noveau: fix reference count leak in nouveau_fbcon_open

nouveau_fbcon_open() calls calls pm_runtime_get_sync() that
increments the reference count. In case of failure, decrement the
ref count before returning the error.
Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_fbcon.c

@@ -189,8 +189,10 @@ nouveau_fbcon_open(struct fb_info *info, int user)
 	struct nouveau_fbdev *fbcon = info->par;
 	struct nouveau_drm *drm = nouveau_drm(fbcon->helper.dev);
 	int ret = pm_runtime_get_sync(drm->dev->dev);
-	if (ret < 0 && ret != -EACCES)
+	if (ret < 0 && ret != -EACCES) {
+		pm_runtime_put(drm->dev->dev);
 		return ret;
+	}
 	return 0;
 }