DO NOT MERGE - SoftVPX: fix nFilledLen overflow am: b7ba49c1a0  -s ours am: c7dd19198c am: 3cb33198d6 am: baba64dd05  -s ours
am: aad3552a45

Change-Id: Iae93ca0778b9d3440671610c66f932fc7e100b39