ARM: EXYNOS: Enable mcpm for dual-cluster exynos5800 SoC

The exynos5800 is very similar to exynos5420. We can re-use
the existing MCPM support for exynos5800 for secondary boot
-up and switching.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>