clk: samsung: Define a common samsung_clk_register_pll()

This patch defines a common samsung_clk_register_pll()
Since pll2550 & pll35xx and pll2650 & pll36xx have exactly same clk ops
implementation, added pll2550 and pll2650 also.

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