nb/intel/nehalem: Disable PEG and IGD based on devicetree

Tested on Thinkpad X201: PEG device hidden.

Change-Id: Ib378458a55e18cc02fc49b3e6d6939d31dd4aa65
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35744
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/lenovo/x201/devicetree.cb b/src/mainboard/lenovo/x201/devicetree.cb
index bf74d71..de6d568 100644
--- a/src/mainboard/lenovo/x201/devicetree.cb
+++ b/src/mainboard/lenovo/x201/devicetree.cb
@@ -48,6 +48,7 @@
 		device pci 00.0 on # Host bridge
 			subsystemid 0x17aa 0x2193
 		end
+		device pci 01.0 off end # PEG
 		device pci 02.0 on # VGA controller
 			subsystemid 0x17aa 0x215a
 		end