[PATCH] nvidiafb: Fixes for new G5

Recent X "nv" driver was fixed for various issues with modern 6xxx and 7xxx
cards.  This patch ports those fixes to nvidiafb.  This makes it work fine
on the 6600 bundled with the newest G5 macs.  I've verified it still works
on the 5200FX of the iMacG5.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>