The first adapters in this family are X2522-10, X2522-25, X2541 and
X2542.

These no longer use PCI BAR 0 for I/O, but use that for memory.  In
other words, BAR 2 on SFN8xxx adapters now becomes BAR 0.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Signed-off-by: Martin Habets <mhabets@solarflare.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>