hwmon: (nct7904) Fix the incorrect value of vsen_mask in nct7904_data struct

Voltage sensors overlap with external temperature sensors. Detect
the multi-function of voltage, thermal diode and thermistor from
register VT_ADC_MD_REG to set value of vsen_mask in nct7904_data
struct.

Signed-off-by: amy.shih <amy.shih@advantech.com.tw>
Link: https://lore.kernel.org/r/20190918084801.9859-1-Amy.Shih@advantech.com.tw


Signed-off-by: Guenter Roeck <linux@roeck-us.net>