Fix decoder memory leak in DMVR
Fix the memory leak caused by allocating memory for m_cYuvPredTempDMVRL0 and m_cYuvPredTempDMVRL1 multiple times at decoder.
Fix the memory leak caused by allocating memory for m_cYuvPredTempDMVRL0 and m_cYuvPredTempDMVRL1 multiple times at decoder.