drm/meson: Use drm_dev_put() instead of drm_dev_unref()

According to 'drivers/gpu/drm/drm_drv.c', 'drm_dev_unref()' is just a
compatibility alias for 'drm_dev_put()'. So use the latter instead.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d4ce46077d3ada7149c4555acfdda8ade4a6cf50.1520885192.git.christophe.jaillet@wanadoo.fr

drivers/gpu/drm/meson/meson_drv.c

@@ -284,7 +284,7 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
 	return 0;
 
 free_drm:
-	drm_dev_unref(drm);
+	drm_dev_put(drm);
 
 	return ret;
 }
@@ -303,7 +303,7 @@ static void meson_drv_unbind(struct device *dev)
 	drm_kms_helper_poll_fini(drm);
 	drm_fbdev_cma_fini(priv->fbdev);
 	drm_mode_config_cleanup(drm);
-	drm_dev_unref(drm);
+	drm_dev_put(drm);
 
 }