According to SPC-4, the sense key for commands that are failed with
INVALID FIELD IN PARAMETER LIST and INVALID FIELD IN CDB should be
ILLEGAL REQUEST (5h) rather than ABORTED COMMAND (Bh).  Without this
patch, a tcm_loop LUN incorrectly gives:

    # sg_raw -r 1 -v /dev/sda 3 1 0 0 ff 0
    Sense Information:
     Fixed format, current;  Sense key: Aborted Command
     Additional sense: Invalid field in cdb
     Raw sense data (in hex):
            70 00 0b 00 00 00 00 0a  00 00 00 00 24 00 00 00
            00 00

While a real SCSI disk gives:

    Sense Information:
     Fixed format, current;  Sense key: Illegal Request
     Additional sense: Invalid field in cdb
     Raw sense data (in hex):
            70 00 05 00 00 00 00 18  00 00 00 00 24 00 00 00
            00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00

with the main point being that the real disk gives a sense key of
ILLEGAL REQUEST (5h).
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>