pinctrl: rockchip: split out verification of mux settings
We need to avoid calling regmap functions from irq handlers, so the next
commit is going to move the call to rockchip_set_mux() into an
irq_bus_sync_unlock handler. But we can't return an error from there so
we still need to check the settings from rockchip_irq_set_type() and we
will use this new rockchip_verify_mux() function from there.