EXYNOS5: Add structure for PMU registers

This patch adds power mananagement registers structure for exynos5 SoC.
Signed-off-by: NRajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: NChander Kashyap <chander.kashyap@linaro.org>
Acked-by: NMinkyu Kang <mk7.kang@samsung.com>