msm: clock-8974: Enable the audio_core_ixfabric_clk in post_init

To be able to access certain audio core registers, the
audio_core_ixfabric_clk needs to be on. Turn it on in
post_init.

Change-Id: I29ab8a80bb01696f362d97f98f53538c85f29a18
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>