clk: samsung: exynos5420: Rename mux parent arrays

This patch renames the mux parent arrays as per the naming
convension followed by the other exynos specific clock drivers.
And it also renames "mout_cpu_kfc" clock to "mout_kfc".

Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>