ASOC: ext-clk: Fix hw init issue caused by CLK upgrade

CLK driver upgrade causes hw->init to be NULL.
Unable to get hw->init from CLK core.
Modify to obtain hw->init from local static data.

Change-Id: I2ffc3e7dfd356cfcb2735336dd67ff70a35328c4
Signed-off-by: Shuai Zhang <quic_shuzhan@quicinc.com>