Process EBD and FBD messages in ERROR state

- OMXCodec::on_message() function drops all OMX messages if
  OMXCodec is in ERROR state
- This can cause EBD/FBD messages containing valid buffers to be
  dropped
- Avoid dropping EBD/FBD messages so that buffer book-keeping is still
  possible

Change-Id: Idc1174b3fa946b26458d49394b87fba1738b228e
Signed-off-by: Iliyan Malchev <malchev@google.com>