mb/google/screebo: Add FW_CONFIG and device for VPU

BUG=b:332488817
TEST=set and unset bit20 in HW_CONFIG and check if VPU(0b.0)
is enabled when bit20 is set, and disabled when cleared

Change-Id: I6d7b35dbf8ac9b0abb42f64a947b4bb94f3c6b0f
Signed-off-by: Jamie Ryu <jamie.m.ryu@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81560
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Varshit Pandya <pandyavarshit@gmail.com>
Reviewed-by: Daniel Kang <daniel.h.kang@intel.com>

src/mainboard/google/rex/variants/screebo/overridetree.cb

@@ -30,6 +30,10 @@ fw_config
 		option WIFI_SAR_ID_0		0
 		option WIFI_SAR_ID_1		1
 	end
+	field VPU 22
+		option VPU_DIS			0
+		option VPU_EN			1
+	end
 end
 
 chip soc/intel/meteorlake
@@ -598,5 +602,8 @@ chip soc/intel/meteorlake
 				end
 			end
 		end
+		device ref vpu on
+			probe VPU VPU_EN
+		end
 	end
 end