udp: use skb_attempt_defer_free()

Move skb freeing from udp recvmsg() path to the cpu
which allocated/received it, as TCP did in linux-5.17.

This increases max thoughput by 20% to 30%, depending
on number of BH producers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250916160951.541279-11-edumazet@google.com


Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>