Support SB600 SATA legacy IDE (DMA enable).

Signed-off-by: Anatoli Antonovitch <antonovi@ati.com>
Cc: Jeff Garzik <jeff@garzik.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>