Required elements: "baudclk", "apb_pclk"
Optional properties:
+- snps,uart-16550-compatible : reflects the value of UART_16550_COMPATIBLE
+ configuration parameter. Define this if your UART does not implement the busy
+ functionality.
- resets : phandle to the parent reset controller.
- reg-shift : quantity to shift the register offsets by. If this property is
not present then the register offsets are not shifted.