pinctrl: exynos: Fix typos in gpio/wkup _irq_mask

To mask GPIO/wakeup IRQ, the corresponding bit in mask register has to
be set.

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>