[Intel-gfx] VAAPI mpeg2 decode support for G45 and GM45 chip

[Zou, Nanhai]

Hi, 
   We have enabled VAAPI support for G45 and GM45 platform.

I have tested it with some high profile 1080p mpeg2 stream.
Using a patched mplayer at 
http://www.splitted-desktop.com/~gbeauchesne/mplayer-vaapi/
I can see CPU usage is dramatically reduced.

Currently, we only support mpeg2 decoding.

Welcome to test it.
The git repo is at git://git.freedesktop.org/git/libva, 
To successful compile the mplayer, you need to choose the libva31 branch.

Thanks
Zou Nan hai