scsi: mpt3sas: Fix error return value in _scsih_expander_add()

When an expander does not contain any 'phys', an appropriate error code -1
should be returned, as done elsewhere in this function. However, we
currently do not explicitly assign this error code to 'rc'. As a result, 0
was incorrectly returned.

Link: https://lore.kernel.org/r/20210514081300.6650-1-thunder.leizhen@huawei.com
Fixes: f92363d1 ("[SCSI] mpt3sas: add new driver supporting 12GB SAS")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpt3sas_scsih.c

@@ -6920,8 +6920,10 @@ _scsih_expander_add(struct MPT3SAS_ADAPTER *ioc, u16 handle)
 		 handle, parent_handle,
 		 (u64)sas_expander->sas_address, sas_expander->num_phys);
 
-	if (!sas_expander->num_phys)
+	if (!sas_expander->num_phys) {
+		rc = -1;
 		goto out_fail;
+	}
 	sas_expander->phy = kcalloc(sas_expander->num_phys,
 	    sizeof(struct _sas_phy), GFP_KERNEL);
 	if (!sas_expander->phy) {