udp6: add missing rehash callback to udplite

After commit 23b0269e ("net: udp6: prefer listeners bound to an
address"), UDP-Lite only works when specifying a local address for
the sockets.

This is related to the problem addressed in the commit 719f8358
("udp: add rehash on connect()"). Moreover, __udp6_lib_lookup() now
looks for a socket immediately in the secondary hash table.

And this issue was found with LTP/network tests as well.

Fixes: 23b0269e

 ("net: udp6: prefer listeners bound to an address")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>