The IB spec does not guarantee that the opcode is available in error
completions. Hence do not rely on it. See also commit 948d1e889e5b
("IB/srp: Introduce srp_handle_qp_err()").
Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: <stable@vger.kernel.org> # v3.8 Signed-off-by: Roland Dreier <roland@purestorage.com>