Some drivers require a way to translate GPIO pins to their IRQ numbers.

This patch adds the .to_irq() gpiolib callback to pinctrl-samsung
driver, which creates (if not present yet) and returns an IRQ mapping
for given GPIO pin.
Signed-off-by: NTomasz Figa <t.figa@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NThomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>