SUNRPC: Teach rpc_pipe.c to use new rpc_peeraddr() API

Hide the details of how the RPC client stores remote peer addresses from
the RPC pipefs implementation.

Test plan:
Connectathon with Kerberos 5 authentication.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/rpc_pipe.c

@@ -327,10 +327,8 @@ rpc_show_info(struct seq_file *m, void *v)
 	seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 	seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 			clnt->cl_prog, clnt->cl_vers);
-	seq_printf(m, "address: %u.%u.%u.%u\n",
-			NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
-	seq_printf(m, "protocol: %s\n",
-			clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
+	seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
+	seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 	return 0;
 }