radeon_hd: Move to using the first found monitor's EDID

* This has positive and negitive effects. Using the
  first monitor's EDID vs the VESA EDID means DisplayPort
  monitors and adaptors function.  I think the benefits
  outweigh the risks at this point.
* Haiku will use the native display mode of the first
  monitor and set it across all attached displays.
* Please open bug reports if you notice and regressions.
radeon_hd: Style fix, no functional change