hwmon: (nct6775) Fix non-existent ALARM warning

hwmon: (nct6775) Fix non-existent ALARM warning

Skip non-existent ALARM attribute to avoid a shift-out-of-bounds
dmesg warning.

Reported-by: Doug Smythies <dsmythies@telus.net>
Closes: https://lore.kernel.org/linux-hwmon/ZQVzdlHgWdFhOVyQ@debian.me/T/#mc69b690660eb50734a6b07506d74a119e0266f1b
Fixes: b7f1f7b2523a ("hwmon: (nct6775) Additional TEMP registers for nct6799")
Signed-off-by: Ahmad Khalifa <ahmad@khalifa.ws>
Link: https://lore.kernel.org/r/20230918184722.2033225-1-ahmad@khalifa.ws
Signed-off-by: Guenter Roeck <linux@roeck-us.net>