compat_ioctl: handle SIOCOUTQNSD

Unlike the normal SIOCOUTQ, SIOCOUTQNSD was never handled in compat
mode. Add it to the common socket compat handler along with similar
ones.

Fixes: 2f4e1b39 ("tcp: ioctl type SIOCOUTQNSD returns amount of data not sent")
Cc: Eric Dumazet <edumazet@google.com>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>