usb: gadget: UMS: Invoke board specific USB cleanup interface

This patch invokes board-specific USB cleanup (board_usb_cleanup)
function in the mass storage gadget

Signed-off-by: Inha Song <ideal.song@samsung.com>

common/cmd_usb_mass_storage.c

@@ -154,6 +154,7 @@ int do_usb_mass_storage(cmd_tbl_t *cmdtp, int flag,
 	}
 exit:
 	g_dnl_unregister();
+	board_usb_cleanup(controller_index, USB_INIT_DEVICE);
 	return CMD_RET_SUCCESS;
 }