[PATCH] tulip: enable multiport NIC BIOS fixups for x86_64

A BIOS bug affecting some multiport tulip NICs requires an irq fixup
in tulip_core.c.  This has only been enabled for i686, but it is
needed for x86_64 as well.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>