pinctrl: at91: move lock/unlock_as_irq calls into request/release

The gpiochip_lock_as_irq call can fail and return an error,
while the irq_startup is not expected to fail (returns an
unsigned int which is not checked by irq core code).

irq_request/release_resources functions have been created
to address this problem.

Move gpiochip_lock/unlock_as_irq calls into
irq_request/release_resources functions to prevent using a
gpio as an irq if the gpiochip_lock_as_irq call failed.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>