agm: free session callback list when closing session

1, In current code, the session cb won't be freed when we
use "agm_session_register_cb(priv->session_id, NULL, ...)"
because the cb becomes the address of ipc_cb func instead
of NULL in ipc.
So we need to refine the action for NULL situation.
2, Fix two memory leaks in agm and ipc.

Change-Id: Ia4258a3c34a3babc14c47bff7240edca30f77d6e
Signed-off-by: Deru Wang <quic_deruwang@quicinc.com>
1 file changed
tree: 11322e5167ff1e8786f1d6f729d086e314682d4e
  1. ipc/
  2. plugins/
  3. service/
  4. snd_parser/
  5. Android.mk
  6. NOTICE
  7. README.md
README.md

agm

Audio Graph Manager