replace a few mov + psrlq with pshufw, there are more cases which could benefit from this but they would require us to duplicate some functions ...
the trick is from various places (my own code in libpostproc, a patch on the x264 list, ...)


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@4608 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b