msm: ext_disp: add audio ops to notify codec status

In some cases the audio codec is not ready when display
is up, while the interface driver doesn't know how to
respond without knowing audio codec's status. So add an
audio ops to support this case.

CRs-Fixed: 2010135
Change-Id: I4a19f57858a5ed2999daefc0192d62bef332453b
Signed-off-by: Ray Zhang <rayz@codeaurora.org>