clk: samsung: exynos7: Add clocks for MSCL block

Add clock support for the MSCL block for Exynos7.

Signed-off-by: Tony K Nadackal <tony.kn@samsung.com>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>