hwmon: (it87) Generalise support for FAN_CTL ON/OFF

Support for FAN_CTL ON/OFF is currently disabled only for IT8603E but
there are severl chips that don't support the configuration bits to turn
off fan control entirely.  Generalise this support for any chip.

Add feature flag FEAT_FANCTL_ONOFF for chips that support configuration
bits for management of fan control off and assign all chips that support
the configuration.

Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230527094756.3464256-1-frank@crawford.emu.id.au


Signed-off-by: Guenter Roeck <linux@roeck-us.net>