svcrdma: Squelch compiler warning when SUNRPC_DEBUG is disabled

  CC [M]  net/sunrpc/xprtrdma/svc_rdma_transport.o
linux/net/sunrpc/xprtrdma/svc_rdma_transport.c: In function ‘svc_rdma_accept’:
linux/net/sunrpc/xprtrdma/svc_rdma_transport.c:452:19: warning: variable ‘sap’ set but not used [-Wunused-but-set-variable]
  struct sockaddr *sap;
                   ^
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -390,8 +390,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	struct ib_qp_init_attr qp_attr;
 	unsigned int ctxts, rq_depth;
 	struct ib_device *dev;
-	struct sockaddr *sap;
 	int ret = 0;
+	RPC_IFDEBUG(struct sockaddr *sap);
 
 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);
 	clear_bit(XPT_CONN, &xprt->xpt_flags);
@@ -525,6 +525,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	if (ret)
 		goto errout;
 
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	dprintk("svcrdma: new connection %p accepted:\n", newxprt);
 	sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
 	dprintk("    local address   : %pIS:%u\n", sap, rpc_get_port(sap));
@@ -535,6 +536,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 	dprintk("    rdma_rw_ctxs    : %d\n", ctxts);
 	dprintk("    max_requests    : %d\n", newxprt->sc_max_requests);
 	dprintk("    ord             : %d\n", conn_param.initiator_depth);
+#endif
 
 	trace_svcrdma_xprt_accept(&newxprt->sc_xprt);
 	return &newxprt->sc_xprt;