ARM: dts: Add basic dts include files for Samsung S3C64xx SoCs

This patch adds basic device tree definitions for Samsung S3C64xx SoCs.

Since all the SoCs in the series are very similar, the files are created
hierarchically - one file for the whole series and then separate files
for particular SoCs including the common one.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>