mpt3sas: delay scsi_add_host call to work with scsi-mq

In _scsih_probe, delay the call to scsi_add_host until the host has been
fully set up.

Otherwise, the default .can_queue value of 1 causes scsi-mq to set the block
layer request queue size to its minimum size, resulting in awful performance.

In _scsih_probe error handling, call mpt3sas_base_detach rather than
scsi_remove_host to properly clean up in reverse order.

In _scsih_remove, call scsi_remove_host earlier to clean up in reverse order.

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@avagotech.com>
Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index c608a61..93ce2b2 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -266,7 +266,7 @@
 	ioc->fault_reset_work_q = NULL;
 	spin_unlock_irqrestore(&ioc->ioc_reset_in_progress_lock, flags);
 	if (wq) {
-		if (!cancel_delayed_work(&ioc->fault_reset_work))
+		if (!cancel_delayed_work_sync(&ioc->fault_reset_work))
 			flush_workqueue(wq);
 		destroy_workqueue(wq);
 	}