q35: Add PCIe switch to example q35 configuration

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

docs/q35-chipset.cfg

@@ -91,6 +91,29 @@
   port = "4"
   chassis = "4"
 
+##
+# Example PCIe switch with two downstream ports
+#
+#[device "pcie-switch-upstream-port-1"]
+#  driver = "x3130-upstream"
+#  bus = "ich9-pcie-port-4"
+#  addr = "00.0"
+#
+#[device "pcie-switch-downstream-port-1-1"]
+#  driver = "xio3130-downstream"
+#  multifunction = "on"
+#  bus = "pcie-switch-upstream-port-1"
+#  addr = "00.0"
+#  port = "1"
+#  chassis = "5"
+#
+#[device "pcie-switch-downstream-port-1-2"]
+#  driver = "xio3130-downstream"
+#  multifunction = "on"
+#  bus = "pcie-switch-upstream-port-1"
+#  addr = "00.1"
+#  port = "1"
+#  chassis = "6"
 
 [device "ich9-ehci-1"]
   driver = "ich9-usb-ehci1"