driver: gpio: npcx: Fix API header

For port_set_bits_raw(), port_clear_bits_raw(), and port_toggle_bits(),
the second parameter sould be gpio_port_pins_t type. Currently, it
doesn't have other side effect, but it sould be fix. This commit fixes
it.

Signed-off-by: Wealian Liao <WHLIAO@nuvoton.com>