There were a large number if incorrect, duplicated, misplaced
registers that were leading to bugs in the code. This is my first
shot at cleaning them up. Luckly as we are using AtomBIOS the number
of registers we need to know about is shrinking.
* remove registers left over from register banging days
* r770 is less then r710, r720 in the drm sources. Fix in code.
* enable newer radeons for testing
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42930 a95241bf-73f2-0310-859d-f6bbb57e9c96
