mb/google/skyrim: Enable internal graphics

BUG=b:214416935
TEST=builds

Signed-off-by: Jon Murphy <jpmurphy@google.com>
Change-Id: Icc71b114bf9d8f70ae38a876eedc9d1c3c02169c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62151
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

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

@@ -6,6 +6,9 @@ chip soc/amd/sabrina
 				device pnp 0c09.0 alias chrome_ec on end
 			end
 		end
+		device ref gpp_bridge_a on  # Internal GPP Bridge 0 to Bus A
+			device ref gfx on end # Internal GPU (GFX)
+		end
 	end # domain
 	device ref uart_0 on end # UART0
 end	# chip soc/amd/sabrina