Decoder: Fix in the case of MMCO 6 Added an error check in the case of MMCO 6 (SET_LT_INDEX) Bug: 38014992 Test: POC fails before / works after patch Change-Id: I76e38a8e2ff0bab043b47f44f1f7b1d4fe60d416 (cherry picked from commit 9e4f0ce7042078aeffaa16f2773cc2d1b82cdb12) (cherry picked from commit 41489f9ece970df8530e28d7a24710b1beb755e2)