clk: samsung: Fix mau_epll clock definition for exynos5422

Parent clock of the MAU_EPLL gate clock on exynos5422 is
"mout_user_mau_epll", not "mout_mau_epll_clk". This change
only affects exynos5422/5800.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>