Input: add driver for the input part of qnap-mcu devices

The MCU controls the power-button and beeper, so expose them as input
device. There is of course no interrupt line, so the status of the
power-button needs to be polled. To generate an event the power-button
also needs to be held for 1-2 seconds, so the polling interval does
not need to be overly fast.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20241107114712.538976-7-heiko@sntech.de


Signed-off-by: Lee Jones <lee@kernel.org>