mb/intel/dg43gt: Program the subsystemid

Change-Id: I9f979e63378b1e0090a57849038eaafeb20d7a40
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/30471
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tristan Corrick <tristan@corrick.kiwi>

src/mainboard/intel/dg43gt/devicetree.cb

@@ -25,6 +25,7 @@ chip northbridge/intel/x4x		# Northbridge
 		end
 	end
 	device domain 0 on		# PCI domain
+		subsystemid 0x8086 0x0028 inherit
 		device pci 0.0 on end			# Host Bridge
 		device pci 2.0 on end			# Integrated graphics controller
 		device pci 2.1 on end			# Integrated graphics controller 2