[dvdplayer] only call OpenDefaultSteams() for PVR streams when the
DMX_SPECIALID_STREAMCHANGE packets comes in. This way we avoid
opening it sooner when the streams are about to change very soon
anyway
[dvdplayer] don't delete the demuxer all the time, it can be reused
[dvdplayer] remove CACHESTATE_PVR completely, move loading of channel settings to separate method