msm: ADSPRPC: Enable Audio PDR support

Register for ADSP Audio PDR notifications and handle Audio PDR
by notifying all the Audio static PD clients.

change-Id: I97f3d2ebb204a276c4266c0d300ff96935e3082e
Acked-by: Himateja Reddy <hmreddy@qti.qualcomm.com>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>