drivers: i2c: npcx: prevent unexpected target address match ISR

This commit prevents the hardware from generating an unexpected
target slave address match ISR by the following change:
1. Enable the New Match Interrupt Enable bit (NMINTEN) only when
   necessary.
2. Explicitly clear all SMBnADDRx registers because they are not
   cleared when the I2C hardware is disabled. It will cause the
   asynchrinization between SMBnADDRx and registered_target_mask if the
   system jumps from the RO image to the RW image.

Signed-off-by: Jun Lin <CHLin56@nuvoton.com>
Signed-off-by: Alvis Sun <yfsun@nuvoton.com>