ARM: EXYNOS: Fix EINT wake-up mask configuration when pinctrl is used

On DT-enabled systems pinctrl-exynos driver is responsible for handling
of wake-up EINT interrupts. This patch adjusts wake-up mask
configuration code to take wake-up mask value from pinctrl-exynos driver
on DT-enabled systems.

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>