net/wan: add MODULE_LICENSE for fsl_ucc_hdlc

It is required to build it as a module.
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wan/fsl_ucc_hdlc.c

@@ -1175,3 +1175,4 @@ static struct platform_driver ucc_hdlc_driver = {
 };
 
 module_platform_driver(ucc_hdlc_driver);
+MODULE_LICENSE("GPL");