Revert "[SCSI] mpt2sas: Remove phys on topology change."

This reverts commit 3520f9c779
("mpt2sas: Remove phys on topology change")

Reverting the previous mpt2sas drives patch changes,
since we will observe below issue

Issue:
Drives connected Enclosure/Expander will unregister with
SCSI Transport Layer, if any one remove and add expander
cable with in DMD (Device Missing Delay) time period or
even any one power-off and power-on the Enclosure with in
the DMD period.

Cc: <stable@vger.kernel.org>
Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/mpt2sas/mpt2sas_transport.c

@@ -1006,12 +1006,9 @@ mpt2sas_transport_update_links(struct MPT2SAS_ADAPTER *ioc,
 		    &mpt2sas_phy->remote_identify);
 		_transport_add_phy_to_an_existing_port(ioc, sas_node,
 		    mpt2sas_phy, mpt2sas_phy->remote_identify.sas_address);
-	} else {
+	} else
 		memset(&mpt2sas_phy->remote_identify, 0 , sizeof(struct
 		    sas_identify));
-		_transport_del_phy_from_an_existing_port(ioc, sas_node,
-		    mpt2sas_phy);
-	}
 
 	if (mpt2sas_phy->phy)
 		mpt2sas_phy->phy->negotiated_linkrate =