clk: samsung: exynos5433: Add binding document for Exynos5433 clock domains

This patch adds devicetree binding document for Exynos5433 SoC system clock
controller.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>