mb/lenovo/t440p: Enable PCI 00:01.1 bridge for dGPU

An optional dGPU can be connected to the second PEG bridge:

  -[0000:00]-+-00.0  Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor DRAM Controller
             +-01.0-[01]--
             +-01.1-[02]----00.0  NVIDIA Corporation GK208M [GeForce GT 730M]

It's possible that the 01.0 bridge is never populated, but we have to
leave it on anyway so 01.1 can be enumerated.

Change-Id: Ieab7a7bf3b31b4ee9d9f12b5d827d866c87356e1
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68099
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/lenovo/haswell/variants/t440p/devicetree.cb b/src/mainboard/lenovo/haswell/variants/t440p/devicetree.cb
index b7588ea..c8772cc 100644
--- a/src/mainboard/lenovo/haswell/variants/t440p/devicetree.cb
+++ b/src/mainboard/lenovo/haswell/variants/t440p/devicetree.cb
@@ -23,8 +23,8 @@
 		subsystemid 0x17aa 0x220e inherit
 
 		device pci 00.0 on  end	# Host bridge
-		device pci 01.0 on  end	# PCIe Bridge for discrete graphics
-		device pci 01.1 off end	# Unused PCIe Bridge
+		device pci 01.0 on  end	# PCIe Bridge for discrete graphics (optional)
+		device pci 01.1 on  end	# PCIe Bridge for discrete graphics (optional)
 		device pci 02.0 on  end	# Internal graphics VGA controller
 		device pci 03.0 on  end	# Mini-HD audio