hwmon: (corsair-psu) add support for critical values

Adds support for reading the critical values of the temperature sensors
and the rail sensors (voltage and current) once and caches them. Updates
the naming of the constants following a more clear scheme. Also updates
the documentation and fixes some typos. Updates is_visible and ops_read
functions to be more readable.

The new sensors output of a Corsair HX850i will look like this:
corsairpsu-hid-3-1
Adapter: HID adapter
v_in:        230.00 V
v_out +12v:   12.14 V  (crit min =  +8.41 V, crit max = +15.59 V)
v_out +5v:     5.03 V  (crit min =  +3.50 V, crit max =  +6.50 V)
v_out +3.3v:   3.30 V  (crit min =  +2.31 V, crit max =  +4.30 V)
psu fan:        0 RPM
vrm temp:     +46.2°C  (crit = +70.0°C)
case temp:    +39.8°C  (crit = +70.0°C)
power total: 152.00 W
power +12v:  108.00 W
power +5v:    41.00 W
power +3.3v:   5.00 W
curr +12v:     9.00 A  (crit max = +85.00 A)
curr +5v:      8.31 A  (crit max = +40.00 A)
curr +3.3v:    1.62 A  (crit max = +40.00 A)

Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
Link: https://lore.kernel.org/r/YFNg6vGk3sQmyqgB@monster.powergraphx.local


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