* QNAP Power Off

QNAP NAS devices have a microcontroller controlling the main power
supply. This microcontroller is connected to UART1 of the Kirkwood and
Orion5x SoCs. Sending the character 'A', at 19200 baud, tells the
microcontroller to turn the power off. This driver adds a handler to
pm_power_off which is called to turn the power off.

Synology NAS devices use a similar scheme, but a different baud rate,
9600, and a different character, '1'.

Required Properties:
- compatible: Should be "qnap,power-off" or "synology,power-off"

- reg: Address and length of the register set for UART1
- clocks: tclk clock
