ARM: dts: Add basic dts for Exynos4412-based Trats 2 board

This patch introduces device tree sources for Samsung Trats 2 board
based on Exynos4412 SoC.

Currently support includes:
 - eMMC,
 - main PMIC (max77686),
 - serial ports,
 - GPIO keys,
 - touchscreen.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>