xprtrdma: Clean up synopsis of frwr_mr_unmap()

Commit 7a03aeb6 ("xprtrdma: Micro-optimize MR DMA-unmapping")
removed the last use of the @r_xprt parameter in this function, but
neglected to remove the parameter itself.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/frwr_ops.c

@@ -54,7 +54,7 @@ static void frwr_cid_init(struct rpcrdma_ep *ep,
 	cid->ci_completion_id = mr->mr_ibmr->res.id;
 }
 
-static void frwr_mr_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
+static void frwr_mr_unmap(struct rpcrdma_mr *mr)
 {
 	if (mr->mr_device) {
 		trace_xprtrdma_mr_unmap(mr);
@@ -73,7 +73,7 @@ void frwr_mr_release(struct rpcrdma_mr *mr)
 {
 	int rc;
 
-	frwr_mr_unmap(mr->mr_xprt, mr);
+	frwr_mr_unmap(mr);
 
 	rc = ib_dereg_mr(mr->mr_ibmr);
 	if (rc)
@@ -84,7 +84,7 @@ void frwr_mr_release(struct rpcrdma_mr *mr)
 
 static void frwr_mr_put(struct rpcrdma_mr *mr)
 {
-	frwr_mr_unmap(mr->mr_xprt, mr);
+	frwr_mr_unmap(mr);
 
 	/* The MR is returned to the req's MR free list instead
 	 * of to the xprt's MR free list. No spinlock is needed.