PCI: Add quirk for devices which disable MSI when INTX_DISABLE is set.

A reasonably common problem with some devices is that they will
disable MSI generation when the INTX_DISABLE bit is set in the
PCI_COMMAND register.

Quirk this explicitly, guarding the pci_intx() calls in msi.c with
this quirk indication.

The first entries for this quirk are for 5714 and 5780 Tigon3 chips,
and thus we can remove the workaround code from the tg3.c driver.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michael Chan <mchan@broadcom.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>