natsemi: Fix detection of vanilla natsemi cards

Bob Tracy <rct@gherkin.frus.com> reported that the addition of support
for Aculab E1/T1 cPCI carrier cards broke detection of vanilla natsemi
cards.  This patch fixes that: the problem is that the driver-specific
ta in the PCI device table is an index into a second table and this
had not been updated for the vanilla cards.

This patch fixes the problem minimally.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>