ARM: EXYNOS: Remove SROM related register settings from mach-exynos

As now we have dedicated driver for SROM controller, it will take care
of saving register banks during S2R so we can safely remove these
settings from mach-exynos.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
[k.kozlowski: Need to select also SAMSUNG_MC]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>