mm-video: vidc: handle reconfiguration and invalid buffers queued

Handle following corner-cases with CTS,
  - Cleanup buffer-list when port buffers are freed to enable
    reconfiguration and reallocation of port buffers
  - Handle invalid buffers (with junk metadata) enqueued with empty
    filled-length.
  - GraphicBufferProducer can enqueue junk meta-buffer with EOS flag
    to signal end-of-stream. Handle this case by queueing a NULL buffer
    marked with EOS to propagate end-of-stream to output buffers.

Change-Id: I1936a918a603f6a02c287737574d837b7356ecf4
CRs-fixed: 515586
2 files changed