clk: samsung: exynos5250: Make names of mux and div clocks consistent

This patch renames all mux clocks to start with mout_ prefix and all div
clocks to start with div_ prefix for consistency with other clocks
already defined this way.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Tomasz Figa <t.figa@samsung.com>