qlcnic: check pci_reset_function result

Static code analyzer complains to unchecked return value.
The result of pci_reset_function() is unchecked.
Despite, the issue is on the FLR supported code path and in that
case reset can be done with pcie_flr(), the patch uses less invasive
approach by adding the result check of pci_reset_function().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7e2cf4fe ("qlcnic: change driver hardware interface mechanism")
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c

@@ -628,7 +628,13 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev)
 	int i, err, ring;
 
 	if (dev->flags & QLCNIC_NEED_FLR) {
-		pci_reset_function(dev->pdev);
+		err = pci_reset_function(dev->pdev);
+		if (err) {
+			dev_err(&dev->pdev->dev,
+				"Adapter reset failed (%d). Please reboot\n",
+				err);
+			return err;
+		}
 		dev->flags &= ~QLCNIC_NEED_FLR;
 	}