scsi: qla2xxx: Drop TARGET_SCF_LOOKUP_LUN_FROM_TAG

Only the __qlt_24xx_handle_abts() code path does not know the LUN for an
abort and it uses the TARGET_SCF_LOOKUP_LUN_FROM_TAG flag to have LIO core
look it up. LIO uses target_lookup_lun_from_tag to go from cmd tag to LUN
for the driver. However, qla2xxx has a tcm_qla2xxx_find_cmd_by_tag() which
does almost the same thing as the LIO helper (it finds the cmd but does not
return the LUN). This patch has qla2xxx use its internal helper.

Link: https://lore.kernel.org/r/1604257174-4524-4-git-send-email-michael.christie@oracle.com
Cc: Nilesh Javali <njavali@marvell.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>