ARM: dts: Move parts common to EXYNOS4 from exynos4210.dtsi to exynos4.dtsi

Most definitions from exynos4210.dtsi can be applied for other SoCs from
EXYNOS4 line as well, so move the common part into separate file that
can be included by dtsi files of other EXYNOS4 SoCs (as well as current
exynos4210.dtsi).

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Thomas Abraham <thomas.abraham@linaro.org>
[kgene.kim@samsung.com: Dongjin Kim <dongjin.kim@agreeyamobility.net>
submitted a similar patch 'Add DTS files derived from common EXYNOS4'
before this but I picked this up because of included exynos4x12 stuff]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>