clk: samsung: pll: Use new registration method for PLL46xx

This patch modifies PLL46xx support code and its users to use the
recently introduced common PLL registration helper.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>