hisi_sas: fix v1 hw check for slot error

Completion header bit CMPLT_HDR_RSPNS_XFRD flags whether the response
frame is received into host memory, and not whether the response frame
has an error.  As such, change the decision on whether a slot has an
error.  Also redundant check on CMPLT_HDR_CMD_CMPLT_MSK is removed.

Fixes: 27a3f229 ("hisi_sas: Add cq interrupt handler")

Signed-off-by: John Garry <john.garry@huawei.com>
Tested-by: Ricardo Salveti <ricardo.salveti@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>