The xircom_tulip_cb driver has been replaced the xircom_cb driver, and
since it depended on BROKEN_ON_SMP it e.g. was no longer present in many
distribution kernels.

This patch therefore removes it.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>