mb/lenovo/t430s: Open PCIe port #5 for Thunderbolt controller

Some T430s variants have a Thunderbolt controller wired to PCIe port

The controller hotplugs itself to the chipset when a downstream device
is hotplugged into it, so the hotplug capability should be enabled on
PCIe port #5.

TODO: find the correct gpio pin to detect the Thunderbolt controller
at runtime.

There are 3 variants of mainboard for Thinkpad T430s: Basic type
(Wistron LSN-4 11263-1), Boards with an additional discreet GPU,
Boards with an additional TB controller (Wistron LSN-4 11271-1),
each of which has a different schematic.

The gpio27 on the last type is set as set as GPIO-INPUT, compared
with GPIO-OUTPUT-HIGH on the basic type boards.

Change-Id: I61f41db100f398069e50e2da8a378b3a8d1c84bf
Signed-off-by: Bill XIE <persmule@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31631
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/mainboard/lenovo/t430s/variants/t430s/overridetree.cb

@@ -1,6 +1,11 @@
 chip northbridge/intel/sandybridge
 	device domain 0 on
 		chip southbridge/intel/bd82x6x # Intel Series 7 Panther Point PCH
+			# Enable hotplug on Port 5 for Thunderbolt controller
+			register "pcie_hotplug_map" = "{ 0, 0, 1, 0, 1, 0, 0, 0 }"
+			device pci 1c.4 on
+				subsystemid 0x17aa 0x21fb
+			end # PCIe Port #5 Thunderbolt controller
 			device pci 1f.0 on
 				chip ec/lenovo/h8
 					register "has_bdc_detection" = "1"