sata_promise: FastTrack TX4200 is a second-generation chip

This patch corrects sata_promise to classify FastTrack TX4200
(DID 3515/3519) as a second-generation chip. Promise's partial-
source FT TX4200 driver confirms this classification.

Treating it as a first-generation chip causes several problems:
1. Detection failures. This is a recent regression triggered by
   the hotplug-enabling changes in 2.6.23-rc1.
2. Various "failed to resume link for reset" warnings.

This patch fixes <http://bugzilla.kernel.org/show_bug.cgi?id=8936>.

Thanks to Stephen Ziemba for reporting the bug and for testing the fix.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Stephen Ziemba <sziemba@ecn.purdue.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>