bareudp: Fix device stats updates.

Bareudp devices update their stats concurrently.
Therefore they need proper atomic increments.

Fixes: 571912c6 ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/04b7b9d0b480158eb3ab4366ec80aa2ab7e41fcb.1725031794.git.gnault@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>