misc: npcm_host_intf: Disable pending KCS/BPC interrupts

misc: npcm_host_intf: Disable pending KCS/BPC interrupts

If there is an unhandled KCS/BPC pending interrupt after reboot,
the KCS/BPC Linux driver may trigger interrupts immediately upon
registering the irq. However, since the driver is not yet initialized
to handle them, this can lead to unexpected behavior.

To prevent this, disable KCS/BPC interrupts in u-boot to avoid pending
interrupts from being raised before the Linux driver is fully initialized.

Signed-off-by: Stanley Chu <yschu@nuvoton.com>
Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>