mb/google/brox: Create greenbayupoc variant

Create the greenbayupoc variant of the brox reference board by copying
the template files to a new directory named for the variant.

BUG=b:329530883
BRANCH=None
TEST=util/abuild/abuild -p none -t google/brox -x -a
make sure the build includes GOOGLE_GREENBAYUPOC.

Change-Id: I90936d97b41e59c49dd92997146caf580bce1f4f
Signed-off-by: Eren Peng <peng.eren@inventec.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81565
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Shelley Chen <shchen@google.com>
diff --git a/src/mainboard/google/brox/Kconfig b/src/mainboard/google/brox/Kconfig
index e7f965a..9bc71ca 100644
--- a/src/mainboard/google/brox/Kconfig
+++ b/src/mainboard/google/brox/Kconfig
@@ -64,6 +64,9 @@
 	select CHROMEOS_WIFI_SAR if CHROMEOS
 	select SOC_INTEL_STORE_ISH_FW_VERSION
 
+config BOARD_GOOGLE_GREENBAYUPOC
+	select BOARD_GOOGLE_BASEBOARD_BROX
+
 if BOARD_GOOGLE_BROX_COMMON
 
 config BASEBOARD_DIR
@@ -114,9 +117,11 @@
 config MAINBOARD_PART_NUMBER
 	default "Brox_Ec_Ish" if BOARD_GOOGLE_BROX_EC_ISH
 	default "Brox" if BOARD_GOOGLE_BROX
+	default "Greenbayupoc" if BOARD_GOOGLE_GREENBAYUPOC
 
 config VARIANT_DIR
 	default "brox" if BOARD_GOOGLE_BROX || BOARD_GOOGLE_BROX_EC_ISH
+	default "greenbayupoc" if BOARD_GOOGLE_GREENBAYUPOC
 
 config VBOOT
 	select VBOOT_LID_SWITCH