mb/google/guybrush: Add chomeec device to lpc bridge

BUG=b:180507937
TEST=builds

Signed-off-by: Mathew King <mathewk@chromium.org>
Change-Id: I7b8b2ab73d66e0aaa0e9b7570661c885f7f777ca
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51296
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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

@@ -42,5 +42,11 @@ chip soc/amd/cezanne
 		device ref gpp_bridge_a on  # Internal GPP Bridge 0 to Bus A
 			device ref gfx on end # Internal GPU (GFX)
 		end
+
+		device ref lpc_bridge on
+			chip ec/google/chromeec
+				device pnp 0c09.0 on end
+			end
+		end
 	end # domain
 end	# chip soc/amd/cezanne