ARM: dts: Add node for interrupt combiner controller on EXYNOS5250

EXYNOS5250 includes a interrupt combiner controller that can group
upto 8 interrupts from different sources and deliver a single combined
interrupt to the GIC. Add a node for the interrupt combiner controller
in the device tree source file.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>