mb/lenovo/t520: Switch to overridetree

Change-Id: If6be9cffe97dcd8f733e3bd5a67a408dd817005a
Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37295
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/lenovo/t520/variants/w520/overridetree.cb b/src/mainboard/lenovo/t520/variants/w520/overridetree.cb
new file mode 100644
index 0000000..3e1c90ee
--- /dev/null
+++ b/src/mainboard/lenovo/t520/variants/w520/overridetree.cb
@@ -0,0 +1,7 @@
+chip northbridge/intel/sandybridge
+	device domain 0 on
+		chip southbridge/intel/bd82x6x # Intel Series 6 Cougar Point PCH
+			device pci 1c.6 on end # PCIe Port #7 USB 3.0
+		end
+	end
+end