hwmon: (nct7904) Fix UNSPECIFIED_INT warning

Fix UNSPECIFIED_INT warning reported by checkpatch.pl

Signed-off-by: Lorenz Kaestle <lorenz.kaestle@fau.de>
Signed-off-by: Jakob Albert <jakob.j.albert@fau.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>