mm-video-v4l2:remove stale entries in m_opq_pmem_q

Remove entries in queue m_opq_pmem_q when video component
moved to loaded state to avoid stale entries usage issue
in execute state when video component moved in below states
Execute -> Idle -> Loaded -> Idle -> Execute.

Author: Maheshwar Ajja <majja@codeaurora.org>

Change-Id: Ieaf2eb33ef517d660d757252c633a89de7958761
CRs-Fixed: 2027721