hwmon (it87): Fix voltage scaling for chips with 10.9mV ADCs

Fix voltage scaling for chips that have 10.9mV ADCs, where scaling was
not performed.

Fixes: ead80803 ("hwmon: (it87) Add support for IT8732F")
Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230318080543.1226700-2-frank@crawford.emu.id.au


[groeck: Update subject and description to focus on bug fix]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>