QSV: reset the encoder at chapter points to force a keyframe

This replaces the mfxEncodeCtrl-based solution used up to this point,
as it's not guaranteed to work with some parameter combinations.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6153 b64f7644-9d1e-0410-96f1-a4d463321fa5
QSV: fix previous commit (outdated version of the same patch, sorry9.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6154 b64f7644-9d1e-0410-96f1-a4d463321fa5