xprtrdma: Relocate the xprtrdma_mr_map trace points

The mr_map trace points were capturing information about the previous
use of the MR rather than about the segment that was just mapped.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/frwr_ops.c

@@ -438,7 +438,6 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
 	mr->mr_nents = ib_dma_map_sg(ia->ri_device, mr->mr_sg, i, mr->mr_dir);
 	if (!mr->mr_nents)
 		goto out_dmamap_err;
-	trace_xprtrdma_mr_map(mr);
 
 	ibmr = frwr->fr_mr;
 	n = ib_map_mr_sg(ibmr, mr->mr_sg, mr->mr_nents, NULL, PAGE_SIZE);
@@ -460,6 +459,7 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
 	mr->mr_handle = ibmr->rkey;
 	mr->mr_length = ibmr->length;
 	mr->mr_offset = ibmr->iova;
+	trace_xprtrdma_mr_map(mr);
 
 	*out = mr;
 	return seg;