hwmon: (f75375s) Fix checkpatch errors and warnings

Clean up driver to follow current coding style.

Cc: Riku Voipio <riku.voipio@iki.fi>
Reviewed-by: Bjoern Gerhart <oss@extracloud.de>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>