This patch adds the missing compatible/description of Exynos-based
boards to remove following build warning.

WARNING: DT compatible string "samsung,..." appears un-documented --
check ./Documentation/devicetree/bindings/
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>