hwmon: (nct7904) Read all SMI status registers in probe function

When nct7904 power up, it compares current sensor readings against the
default threshold immediately. This results in false alarms on startup.
Read all SMI status registers in probe function to clear the alarms.

Signed-off-by: Amy Shih <amy.shih@advantech.com.tw>
[groeck: Reworded description]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>