radeonfb: fix panning corruption on a large virtual screen, Make panning
and copyarea() play nicely with each other.
Signed-off-by: David Eger <eger@havoc.gtf.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>