dm: imx: serial: add i.MX6UL support

Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>

drivers/serial/serial_mxc.c

@@ -365,6 +365,7 @@ static int mxc_serial_ofdata_to_platdata(struct udevice *dev)
 }
 
 static const struct udevice_id mxc_serial_ids[] = {
+	{ .compatible = "fsl,imx6ul-uart" },
 	{ .compatible = "fsl,imx7d-uart" },
 	{ }
 };