pinctrl: sunxi: Implement multiple interrupt banks support

The A23 and A31 support multiple interrupt banks. Support it by adding a linear
domain covering all the banks. It's trickier than it should because there's an
interrupt per bank, so we have multiple interrupts using the same domain.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>