clk: samsung: Migrate exynos5420 to use common samsung_clk_register_pll()

This patch migrates exynos5420 pll registeration to use common
samsung_clk_register_pll() by intialising table of PLLs and adding PLLs to
unique id list of clocks.

Signed-off-by: Yadwinder Singh Brar <yadi.brar@samsung.com>
Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>