PCI: mediatek: Drop error data fabrication when config read fails

If config pci_ops.read() methods return failure, the PCI_OP_READ() and
PCI_USER_READ_CONFIG() wrappers use PCI_SET_ERROR_RESPONSE() to set the
data value, so there's no need to set it in the pci_ops.read() methods
themselves.

Drop the unnecessary data value fabrication when pci_ops.read() fails.

Link: https://lore.kernel.org/r/666127469482f9ca177805ff52aeb7bccb26e4c9.1637243717.git.naveennaidu479@gmail.comSigned-off-by: NNaveen Naidu <naveennaidu479@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/controller/pcie-mediatek.c

@@ -365,19 +365,12 @@ static int mtk_pcie_config_read(struct pci_bus *bus, unsigned int devfn,
 {
 	struct mtk_pcie_port *port;
 	u32 bn = bus->number;
-	int ret;
 
 	port = mtk_pcie_find_port(bus, devfn);
-	if (!port) {
-		*val = ~0;
+	if (!port)
 		return PCIBIOS_DEVICE_NOT_FOUND;
-	}
-
-	ret = mtk_pcie_hw_rd_cfg(port, bn, devfn, where, size, val);
-	if (ret)
-		*val = ~0;
 
-	return ret;
+	return mtk_pcie_hw_rd_cfg(port, bn, devfn, where, size, val);
 }
 
 static int mtk_pcie_config_write(struct pci_bus *bus, unsigned int devfn,