Add support for g761 PWM Fan controller. This is an exact copy of g763
with the difference that it does also support an internal clock
oscillator.

With clocks property not defined, the internal clock oscillator is used.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240604164348.542-2-ansuelsmth@gmail.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>