scsi: libsas: make the lldd_port_deformed method optional

Now LLDDs have to implement lldd_port_deformed method otherwise NULL
dereference will happen. Make it optional and remove the dummy implementation
in hisi_sas.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: Johannes Thumshirn <jthumshirn@suse.de>
CC: Ewan Milne <emilne@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Tomas Henzl <thenzl@redhat.com>
CC: Dan Williams <dan.j.williams@intel.com>
CC: Hannes Reinecke <hare@suse.com>
Acked-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -1861,10 +1861,6 @@ static void hisi_sas_port_formed(struct asd_sas_phy *sas_phy)
 	hisi_sas_port_notify_formed(sas_phy);
 }
 
-static void hisi_sas_port_deformed(struct asd_sas_phy *sas_phy)
-{
-}
-
 static int hisi_sas_write_gpio(struct sas_ha_struct *sha, u8 reg_type,
 			u8 reg_index, u8 reg_count, u8 *write_data)
 {
@@ -1956,7 +1952,6 @@ static struct sas_domain_function_template hisi_sas_transport_ops = {
 	.lldd_query_task	= hisi_sas_query_task,
 	.lldd_clear_nexus_ha	= hisi_sas_clear_nexus_ha,
 	.lldd_port_formed	= hisi_sas_port_formed,
-	.lldd_port_deformed = hisi_sas_port_deformed,
 	.lldd_write_gpio	= hisi_sas_write_gpio,
 };
 

drivers/scsi/libsas/sas_discover.c

@@ -260,7 +260,7 @@ static void sas_suspend_devices(struct work_struct *work)
 	 * phy_list is not being mutated
 	 */
 	list_for_each_entry(phy, &port->phy_list, port_phy_el) {
-		if (si->dft->lldd_port_formed)
+		if (si->dft->lldd_port_deformed)
 			si->dft->lldd_port_deformed(phy);
 		phy->suspended = 1;
 		port->suspended = 1;