xprtrdma: Expose transport header errors

For better observability of parsing errors, return the error code
generated in the decoders to the upper layer consumer.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/rpc_rdma.c

@@ -1246,7 +1246,6 @@ out:
 out_badheader:
 	trace_xprtrdma_reply_hdr(rep);
 	r_xprt->rx_stats.bad_reply_count++;
-	status = -EIO;
 	goto out;
 }