clk: hi3620: Move const initdata into correct code section

Use __initconst instead of __initdata for constant init data.

Signed-off-by: Bintian Wang <bintian.wang@huawei.com>
Acked-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>