PCI: dwc: Return directly when num-lanes is not found

The num-lanes is optional since it is not needed on some platforms
that bring up the link in firmware.

The link programming is based on the num-lanes properties (which is
optional); if it is not present code must return instead of fiddling
with the lanes value to print an error message.
Signed-off-by: NHou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NAndrew Murray <andrew.murray@arm.com>

drivers/pci/controller/dwc/pcie-designware.c

@@ -423,8 +423,10 @@ void dw_pcie_setup(struct dw_pcie *pci)
 
 
 	ret = of_property_read_u32(np, "num-lanes", &lanes);
-	if (ret)
-		lanes = 0;
+	if (ret) {
+		dev_dbg(pci->dev, "property num-lanes isn't found\n");
+		return;
+	}
 
 	/* Set the number of lanes */
 	val = dw_pcie_readl_dbi(pci, PCIE_PORT_LINK_CONTROL);