pinctrl: iproc: Set irq handler based on trig type

Rather than always using handle_simple_irq() as the gpio_irq_chip
handler, set a more appropriate handler based on the IRQ trigger type
requested.
This is important for level triggered interrupts which need to be
masked during handling.

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Link: https://lore.kernel.org/r/20191215210503.15488-2-hamish.martin@alliedtelesis.co.nz


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>