s3:winbindd: make use of samba_sockaddr in set_remote_addresses() to avoid warnings

s3:winbindd: make use of samba_sockaddr in set_remote_addresses() to avoid warnings

../../source3/winbindd/winbindd_dual_ndr.c: In function ‘set_remote_addresses’:
../../source3/winbindd/winbindd_dual_ndr.c:467:51: warning: dereferencing type-punned pointer might break strict-aliasing rules [-Wstrict-aliasing]
  467 |         struct sockaddr *sar = (struct sockaddr *)&st;

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>