netdev-genl: remove rtnl_lock protection from NAPI ops

NAPI lifetime, visibility and config are all fully under
netdev_lock protection now.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250115035319.559603-12-kuba@kernel.org


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