add VC-1 MMX DSP functions, under MIT license.

patch by Christophe GISQUET %christophe P gisquet A free P fr%
original thread:
date: Jul 7, 2007 12:52 PM
subject: [FFmpeg-devel] [PATCH] VC-1 MMX DSP functions

Originally committed as revision 11074 to svn://svn.ffmpeg.org/ffmpeg/trunk