ARM: dts: exynos: Use human-friendly symbols for interrupt properties in exynos5

Replace hard-coded values of type of GIC interrupt and its flags with
respective macros from header to increase code readability.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>