net/socket: convert sock_map_fd() to FD_ADD()

static int sock_map_fd(struct socket *sock, int flags)

{

	struct file *newfile;

	int fd = get_unused_fd_flags(flags);

	if (unlikely(fd < 0)) {

		sock_release(sock);

		return fd;

	}

	int fd;

	newfile = sock_alloc_file(sock, flags, NULL);

	if (!IS_ERR(newfile)) {

		fd_install(fd, newfile);

	fd = FD_ADD(flags, sock_alloc_file(sock, flags, NULL));

	if (fd < 0)

		sock_release(sock);

	return fd;

}

	put_unused_fd(fd);

	return PTR_ERR(newfile);

}

/**

 *	sock_from_file - Return the &socket bounded to @file.

 *	@file: file