hwmon: (nct6775) Convert S_I* permissions macros to octal

Checkpatch has been warning about these for a while; the octal
versions are both more comprehensible and more concise.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20220427010154.29749-6-zev@bewilderbeest.net
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>