um: vector: Eliminate the dependency on uml_net

um: vector: Eliminate the dependency on uml_net

The only dependency on uml_net (i.e., the legacy network transport
infrastructure) is the call to uml_net_setup_etheraddr(). Implement
it inside vector to eliminate the uml_net dependency completely. It
will allow us to remove uml_net in the next step.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://patch.msgid.link/20250503051710.3286595-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>