Initialize sco codecs supported with CVSD

Usecase:
1. Connect headset/carkit supporting codec negotiation
   but does not send AT+BAC with available codecs.
2. Make a call and create SCO connection.
3. Transfer audio to AG from headset/carkit.
4. Transfer audio back to carkit.

Failure:
AG will not establish SCO connection with remote.

Rootcause:
We initialize codecs supported by remote as 0 and update
it with codecs received as part of AT+BAC. When AG sends
+BCS to start codec negotiation, it received AT+BCS=1 from
remote. Since 1 is not in the list of remote supported codecs
(0), AG will not create SCO connection in step#4.

Fix:
Initialize sco codecs supported by remote with mandatory
codec, CVSD.

Change-Id: Ibe0e1a7bd3e59e8618568d320acfbde88f3fc11e