svcrdma: Remove superfluous line from rdma_read_chunks()

Clean up: svc_rdma_get_read_chunk() already returns a pointer
to the Read list. No need to set "ch" again to the value it
already contains.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

@@ -447,10 +447,8 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
 	head->arg.len = rqstp->rq_arg.len;
 	head->arg.buflen = rqstp->rq_arg.buflen;
 
-	ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
-	position = be32_to_cpu(ch->rc_position);
-
 	/* RDMA_NOMSG: RDMA READ data should land just after RDMA RECV data */
+	position = be32_to_cpu(ch->rc_position);
 	if (position == 0) {
 		head->arg.pages = &head->pages[0];
 		page_offset = head->byte_len;