clk: samsung: pll: Use new registration method for PLL6552 and PLL6553

This patch modifies PLL6552 and PLL6553 clock drivers to use recently
added common Samsung PLL registration method.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>