ARM: dts: exynos: Move common Exynos5410/542x/5800 nodes to new DTSI

The Exynos5410/542x/5800 are very similar designs. Create a new
DTSI with common nodes to remove DTS duplication. Although currently
only MCT and SysRAM are shared but in future more nodes will be added to
the common file.

The patch should not have functional impact.

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