Add support for SND event framework for helping with
notifications among different audio modules/drivers.
The SND event framework functions with a master/client
mechanism, where each client and the master register
with the framework, and then notifies its own status
(UP/DOWN). Each master will share a list of clients it
is interested in, and once all the clients are registered
and notified UP, the framework's state will be UP. On the
other hand, as and when any one of the client, or the master
reports its state as DOWN while the framework is UP, the
framework state would be changed to DOWN, and all clients
and the master would be let know about the change.
Change-Id: Ief6f26c5d5626c29246472ad71c247d71ee9e92f
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
06183689db