mb/google/skyrim/baseboard/devicetree: enable mp2 device

The mp2 PCI device is still present when no mp2 firmware is loaded. When
this device isn't explicitly enabled in the mainboard's devicetree, the
chipset devicetree default of the device being disabled is used. This
results in coreboot's resource allocator not allocating resources to the
device and since the bridge doesn't have enough MMIO space reserved, the
Linux kernel can't assign resources to it. To fix this problem, enable
the mp2 device in the mainboard's devicetree so that it gets its
resources assigned by coreboot. An equivalent change was verified on
Chausie.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I1076ccacc6f51bf195b8280a6df5ad1849771519
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72196
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/skyrim/variants/baseboard/devicetree.cb

@@ -162,6 +162,7 @@ chip soc/amd/mendocino
 				end
 			end
 			device ref acp on end # Audio Processor (ACP)
+			device ref mp2 on end # Sensor Fusion Hub (MP2)
 		end
 		device ref gpp_bridge_c on  # Internal GPP Bridge 2 to Bus C
 			device ref xhci_2 on # USB 2.0 (USB2)