clk: hisi: remove static variable

Remove the static variable. So these common clock register helper could
be used in more SoCs.

Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>

diff --cc drivers/clk/hisilicon/clk-hi3620.c
Simple merge

diff --cc drivers/clk/hisilicon/clk-hip04.c
Simple merge

diff --cc drivers/clk/hisilicon/clk.c
Simple merge

diff --cc drivers/clk/hisilicon/clk.h
Simple merge