ARM: EXYNOS: Allow wake-up using GIC interrupts

This patch restores the ability to receive wake-up events from internal
GIC interrupts, e.g. RTC tick or alarm interrupts.

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