clk: hi3660: fix wrong parent name of clk_mux_sysbus

Parent name of clk_mux_sysbus is not correct. This patch fixes it.

Signed-off-by: Chen Jun <chenjun14@huawei.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>