ARM: dts: Add basic dts file for Samsung Trats board

This commit adds basic device tree for Exynos4210-based Trats board.
Currently it provides support for eMMC over sdhci and MAX8997 PMIC.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>