net: pass a sockptr_t into ->setsockopt

Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer.  This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -3211,7 +3211,7 @@ EXPORT_SYMBOL(sock_common_recvmsg);
  *	Set socket options on an inet socket.
  */
 int sock_common_setsockopt(struct socket *sock, int level, int optname,
-			   char __user *optval, unsigned int optlen)
+			   sockptr_t optval, unsigned int optlen)
 {
 	struct sock *sk = sock->sk;