radeon tv-out

[Alex Deucher]

I've just pushed tv-out support to the radeon randr-1.2 branch.  Many
thanks to Federico Ulivi and all who helped get the GATOS code
re-licensed.   I used a good bit of it as the base.  It should in
theory support all chips with integrated tv-out.

Current status:
- only tested on rv350
- only 800x600 is supported at the moment
- only composite/s-video support (no component)
- no detection for tv-out yet.  you'll have to force it on or edit
radeon_detect()
- only chips with integrated tv-out are supported (no theater tv-out)
- only tested NTSC

Plans:
- add proper load detection
- add tv-out attributes to adjust the image
- add support for other modes

Have fun!

Alex