msm: vidc: kill session without acquiring lock

Mutex lock q->lock was already acquired before calling
start_streaming() so calling msm_comm_kill_session() from
inside start_streaming() may result in abort timeout error.
Kill session will send abort to firmware and waits for
abort done response which may not be processed ever if
response handler thread tries to acquire same q->lock.
All timeout errors are treated as fatal error so avoid
timeout error by moving msm_comm_kill_session() from inside
start_streaming() to after releasing q->lock functionality.

CRs-Fixed: 2135048
Change-Id: I01b25bb76b7191cf4df656a9b05363ea3529bdb9
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>