net, misc: replace uses of NIP6_FMT with %p6

net/netlabel/netlabel_addrlist.c

net/sctp/ipv6.c

net/sctp/sm_statefuns.c

net/sunrpc/clnt.c

net/sunrpc/rpcb_clnt.c

net/sunrpc/svcauth_unix.c

net/sunrpc/xprtsock.c

net/xfrm/xfrm_policy.c

net/xfrm/xfrm_state.c