Revert "svcrdma: Do not send XDR roundup bytes for a write chunk"

This reverts commit 6f18dc89.

Just as one example, it appears this code could do the wrong thing in
the case of a two-byte NFS READ that crosses a page boundary.

Chuck says: "In that case, nfsd would pass down an xdr_buf that has one
byte in a page, one byte in another page, and a two-byte XDR pad. The
logic introduced by this optimization would be fooled, and neither the
second byte nor the XDR pad would be written to the client."

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprtrdma/svc_rdma_sendto.c

@@ -342,13 +342,6 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
 						arg_ch->rs_handle,
 						arg_ch->rs_offset,
 						write_len);
-
-		/* Do not send XDR pad bytes */
-		if (chunk_no && write_len < 4) {
-			chunk_no++;
-			break;
-		}
-
 		chunk_off = 0;
 		while (write_len) {
 			ret = send_write(xprt, rqstp,