clk: mux: assign init data

The original conversion to struct clk_hw_init failed to add the pointer
assignment in clk_register_mux.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Reported-by: Sascha Hauer <s.hauer@pengutronix.de>

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