lockd: Support non-AF_INET addresses in nlm_lookup_host()

Use struct sockaddr * and length in nlm_lookup_host_info to all callers
to pass in either AF_INET or AF_INET6 addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>