msm: cpp: Check for validity of processed frame in cpp timeout

Device crash seen from cpp timeout when process frame is invalid.
Check for validity of processed frame in timeout when queue length
is valid. Clear and release the buffers once the scenario is
detected.

CRs-Fixed: 2001828
Change-Id: If4fdfc993576e44e866aa30afd83d6236b3de276
Signed-off-by: Krishnankutty Kolathappilly <kkolatha@codeaurora.org>