msm: vidc: Add support for decoder STOP command

Decoder STOP command is to signal HW that this is the EOS
buffer. HW returns all the pending ETB's and FTB's. One of
the FTB_DONE's will have EOS flag back to client. With this,
driver don't need to support zero_bytes_used input buffers.

CRs-Fixed: 2078801
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>
Change-Id: I44c60db1c98707501b5637eba5d1d81663d6a722