ARM: dts: Update device tree source files for EXYNOS5250

Update EXYNOS5 device tree source files for EXYNOS5250 SoC.
This includes new additions to the EXYNOS5 dtsi and SMDK5250
dts files and few minor fixes.

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