net/handshake: Remove unneeded check from handshake_dup()

handshake_req_submit() now verifies that the socket has a file.

Fixes: 3b3009ea8a ("net/handshake: Create a NETLINK service for handling handshake requests")
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/handshake/netlink.c

@@ -99,9 +99,6 @@ static int handshake_dup(struct socket *sock)
 	struct file *file;
 	int newfd;
 
-	if (!sock->file)
-		return -EBADF;
-
 	file = get_file(sock->file);
 	newfd = get_unused_fd_flags(O_CLOEXEC);
 	if (newfd < 0) {