pinctrl: rockchip: add irq_enable & irq_disable ops

Currently we are trying to enable/disable the clk of irq's gpio bank when
unmask/mask irq. But the kernel's "lazy disable approach" will skip masking
irq when the irq chip doesn't support irq_disable ops.

So we may hit this case:
	irq_enable-> enable clk
	irq_disable-> noop
	irq_enable-> enable clk again
	irq_disable-> noop

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>