pinctrl: coh901: move irq line locking to resource callbacks

This switches the COH901 GPIO driver over to using the
.request_resources() and .release_resources() callbacks from
the irqchip vtable and separate the calls from the .enable()
and .disable() callbacks as the latter cannot really say no
to a request, whereas the resource callbacks can.

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