udp_ioctl() really handles UDP and UDPLite protocols.

1) It can increment UDP_MIB_INERRORS in case first_packet_length() finds
a frame with bad checksum.

2) It has a dependency on sizeof(struct udphdr), not applicable to
ICMP/PING

If ping sockets need to handle SIOCINQ/SIOCOUTQ ioctl, this should be
done differently.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>