clk/samsung: add support for pll2550xx

exynos5260 use pll2550xx and it has different bit fields
for P,M,S values as compared to pll2550. Support for
pll2550xx is added here.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Rahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: Arun Kumar K <arun.kk@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>