PCI: latency timer doesn't apply to PCIe

The latency timer is read-only and hardwired to zero for all PCIe
devices, both Type 0 and Type 1, so don't bother trying to update it
and cluttering the dmesg log with meaningless "setting latency timer
to 64" messages.
Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pci.c

@@ -2613,6 +2613,10 @@ void __weak pcibios_set_master(struct pci_dev *dev)
 {
 	u8 lat;
 
+	/* The latency timer doesn't apply to PCIe (either Type 0 or Type 1) */
+	if (pci_is_pcie(dev))
+		return;
+
 	pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
 	if (lat < 16)
 		lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;