scsi: core: Delete scsi_use_blk_mq

Module param scsi_use_blk_mq has not been referenced for some time, so zap
it.

Link: https://lore.kernel.org/r/1581355992-139274-1-git-send-email-john.garry@huawei.com
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi.c

@@ -764,10 +764,6 @@ MODULE_LICENSE("GPL");
 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
 
-/* This should go away in the future, it doesn't do anything anymore */
-bool scsi_use_blk_mq = true;
-module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
-
 static int __init init_scsi(void)
 {
 	int error;