pinctrl: sunxi: fix gpiochip_lock_as_irq() failure when pinmux is unknown

pinctrl: sunxi: fix gpiochip_lock_as_irq() failure when pinmux is unknown

Fixes kernel hang during boot due to inability to set up IRQ on AXP313a.

The issue is caused by gpiochip_lock_as_irq() which is failing when gpio
is in uninitialized state.

Solution is to set pinmux to GPIO INPUT in
sunxi_pinctrl_irq_request_resources() if it wasn't initialized
earlier.

Tested on Orange Pi Zero 3.

Fixes: 01e10d0272b9 ("pinctrl: sunxi: Implement gpiochip::get_direction()")
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Chen-Yu Tsai <wens@kernel.org>
Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
Signed-off-by: Linus Walleij <linusw@kernel.org>