drm/rockchip: Replace drm_dev_unref with drm_dev_put

This patch unifies the naming of DRM functions for reference counting
of struct drm_device. The resulting code is more aligned with the rest
of the Linux kernel interfaces.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180717110927.30776-1-tzimmermann@suse.de

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

@@ -184,7 +184,7 @@ static int rockchip_drm_bind(struct device *dev)
 err_free:
 	drm_dev->dev_private = NULL;
 	dev_set_drvdata(dev, NULL);
-	drm_dev_unref(drm_dev);
+	drm_dev_put(drm_dev);
 	return ret;
 }
 
@@ -204,7 +204,7 @@ static void rockchip_drm_unbind(struct device *dev)
 
 	drm_dev->dev_private = NULL;
 	dev_set_drvdata(dev, NULL);
-	drm_dev_unref(drm_dev);
+	drm_dev_put(drm_dev);
 }
 
 static const struct file_operations rockchip_drm_driver_fops = {