pinctrl: exynos: Handle only unmasked wakeup interrupts

A bit in EINTxx_PEND register is set regardless of interrupt mask, which
causes spurious interrupts. To avoid them, the read value of pending
register must be masked with current interrupt mask manually.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>