Prevent OOB write in soft_avc encoder am: 463452a949 am: 97db64baf6 am: b6bf46944f am: cd35c846f0 am: a43be7d42d am: 3c375611d6
am: 96b4e70f44

Change-Id: Id6038e76dc85b326dd701a4d0916bd8f7591c949