ARM: dts: Remove combiner IRQ node from exynos4x12.dtsi

These nodes have separately been added to 4212 and 4412 dtsi
files by commit 30269ddf ("ARM: exynos: add missing properties
for combiner IRQs"). The existing node also contained a few
incorrect entries.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>