In order to support DT for mmp SOC clocks, it defines
some basic APIs which are shared by all mmp SOC clock
units.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>