net: hns3: add a check to pointer in error_detected and slot_reset

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

If we add a VF without loading hclgevf.ko and then there is a RAS error
occurs, PCIe AER will call error_detected and slot_reset of all functions,
and will get a NULL pointer when we check ad_dev->ops->handle_hw_ras_error.
This will cause a call trace and failures on handling of follow-up RAS
errors.
This patch check ae_dev and ad_dev->ops at first to solve above issues.

Feature or Bugfix: Bugfix
Signed-off-by: Nliweihang <liweihang@huawei.com>
Reviewed-by: Nlipeng <lipeng321@huawei.com>
Reviewed-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -1957,9 +1957,9 @@ static pci_ers_result_t hns3_error_detected(struct pci_dev *pdev,
 	if (state == pci_channel_io_perm_failure)
 		return PCI_ERS_RESULT_DISCONNECT;
 
-	if (!ae_dev) {
+	if (!ae_dev || !ae_dev->ops) {
 		dev_err(&pdev->dev,
-			"Can't recover - error happened during device init\n");
+			"Can't recover - error happened before device initialized\n");
 		return PCI_ERS_RESULT_NONE;
 	}
 
@@ -1977,6 +1977,9 @@ static pci_ers_result_t hns3_slot_reset(struct pci_dev *pdev)
 	struct device *dev = &pdev->dev;
 	enum hnae3_reset_type reset_type;
 
+	if (!ae_dev || !ae_dev->ops)
+		return PCI_ERS_RESULT_NONE;
+
 	/* request the reset */
 	if (ae_dev->ops->reset_event) {
 		if (!ae_dev->override_pci_need_reset) {