gpio: siox: Switch to IRQ_TYPE_NONE

The siox driver is hardcoding a default type of
IRQ_TYPE_EDGE_RISING to the irq helper, but this should only
be applicable to old boardfiles and odd device tree irqchips
with just onecell irq (no flags). I doubt this is the case
with the siox, I think all consumers specify the flags they
use in the device tree.

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>