net/handshake: use sockfd_put() helper

Replace fput() with sockfd_put() in handshake_nl_done_doit().

Signed-off-by: A K M Fazla Mehrab <a.mehrab@bytedance.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20240826182652.2449359-1-a.mehrab@bytedance.com


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