[automerger skipped] libhevcenc: fix bitrate overshoot when lookahead is disabled am: f5ec0d4287 -s ours

am skip reason: Change-Id I6dcf9fb52d3aa18935e0b8d9ec9c193b15d30668 with SHA-1 fa4b60c764 is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libhevc/+/12959016

Change-Id: I4b46c50536361afa8c6cdb26f3d81aad336420c9