Now only fixed rate clocks are appended into the clock driver.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@linaro.org>

Enable common clock driver of Hi3620 SoC. clkgate-seperated driver is
used to support the clock gate that enable/disable/status registers
are seperated.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@gmail.com>