svcrdma: Fix stale comment

Commit 7d81ee87 ("svcrdma: Single-stage RDMA Read") changed the
behavior of svc_rdma_recvfrom() but neglected to update the
documenting comment.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

@@ -771,9 +771,6 @@ static bool svc_rdma_is_reverse_direction_reply(struct svc_xprt *xprt,
  *
  * The next ctxt is removed from the "receive" lists.
  *
- * - If the ctxt completes a Read, then finish assembling the Call
- *   message and return the number of bytes in the message.
- *
  * - If the ctxt completes a Receive, then construct the Call
  *   message from the contents of the Receive buffer.
  *
@@ -782,7 +779,8 @@ static bool svc_rdma_is_reverse_direction_reply(struct svc_xprt *xprt,
  *     in the message.
  *
  *   - If there are Read chunks in this message, post Read WRs to
- *     pull that payload and return 0.
+ *     pull that payload. When the Read WRs complete, build the
+ *     full message and return the number of bytes in it.
  */
 int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 {