pinctrl: exynos: Add support for set_irq_wake of wake-up EINTs

This patch adds support of IRQ wake-up ability configuration for
wake-up EINTs on Exynos SoCs.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>