QSV: don't print BPyramid value when it's not supported by the implementation used, as it's somewhat pointless (would always say off anyway).

This also allows to notice whether b-pyramid is available more quickly when reading the log.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5930 b64f7644-9d1e-0410-96f1-a4d463321fa5