hwmon: (it87) Allow disabling exiting of configuration mode

Disabling configuration mode on some chips can result in system
hang-ups and access failures to the Super-IO chip at the
second SIO address. Never exit configuration mode on these
chips to avoid the problem.

This patch should be applied in conjunction with a previous one to
initialise the second chip for certain mother boards.

Signed-off-by: Frank Crawford <frank@crawford.emu.id.au>
Link: https://lore.kernel.org/r/20230128060308.1549707-2-frank@crawford.emu.id.au


[groeck: Change feature bit from 28 to 19 to be continuous]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>