ARM: S5P: Add support for MFC device

Add support for MFC device to plat-s5p, mach-exynos4, mach-s5pv210:
 - clock support
 - memory mapping and reserving
 - s5p_device_mfc platform device

Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>