* Serial

Currently defined compatibles:
- ucc_uart

Properties for ucc_uart:
device_type : which type the device is
port-number : port number of UCC-UART
rx-clock-name : which clock QE use for RX
tx-clock-name : which clock QE use for TX

Example:

	serial: ucc@2200 {
		device_type = "serial";
		compatible = "ucc_uart";
		port-number = <1>;
		rx-clock-name = "brg2";
		tx-clock-name = "brg2";
	};
