pinctrl: samsung: Use per-bank IRQ domain for wake-up interrupts

This patch reworks wake-up interrupt handling in pinctrl-exynos driver,
so each pin bank, which provides wake-up interrupts, has its own IRQ
domain.

Information about whether given pin bank provides wake-up interrupts,
how many and whether they are separate or muxed are parsed from device
tree.

It gives following advantages:
  - interrupts can be specified in device tree in a more readable way,
    e.g. :
    	device {
		/* ... */
		interrupt-parent = <&gpx2>;
		interrupts = <4 0>;
		/* ... */
	};
  - the amount and layout of interrupts is not hardcoded in the code
    anymore, but defined in SoC-specific structure
  - bank and pin of each wake-up interrupt can be easily identified, to
    allow operations, such as setting the pin to EINT function, from
    irq_set_type() callback

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>