compat_ioctl: move SIOCOUTQ out of compat_ioctl.c

All users of this call are in socket or tty code, so handling
it there means we can avoid the table entry in fs/compat_ioctl.c.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>