hwmon: Support ADI Fan Control IP

hwmon: Support ADI Fan Control IP

The purpose of this IP Core is to control the fan used for the cooling of a
Xilinx Zynq Ultrascale+ MPSoC without the need of any external temperature
sensors. To achieve this, the IP core uses the PL SYSMONE4 primitive to
obtain the PL temperature and, based on those readings, it then outputs
a PWM signal to control the fan rotation accordingly.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20191009102806.262241-1-nuno.sa@analog.com
[groeck: adi,pulses-per-revolution -> pulses-per-revolution;
 dropped unused 'res' from probe function]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>