mb/google/nissa: Create sundance variant

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

Due to new_variant.py limitation that repo can no longer be used in
inside, created this CL manually following google suggestion.

BUG=b:328505938
TEST=util/abuild/abuild -p none -t google/brya -x -a
make sure the build includes GOOGLE_SUNDANCE

Change-Id: Ia8ba318f18d2cac69898687311631778e61bf2ea
Signed-off-by: Leo Chou <leo.chou@lcfc.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81347
Reviewed-by: Derek Huang <derekhuang@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Shou-Chieh Hsu <shouchieh@google.com>
diff --git a/src/mainboard/google/brya/Kconfig b/src/mainboard/google/brya/Kconfig
index 992be88..160d12a 100644
--- a/src/mainboard/google/brya/Kconfig
+++ b/src/mainboard/google/brya/Kconfig
@@ -382,6 +382,9 @@
 	select HAVE_WWAN_POWER_SEQUENCE
 	select INTEL_GMA_HAVE_VBT
 
+config BOARD_GOOGLE_SUNDANCE
+	select BOARD_GOOGLE_BASEBOARD_NISSA
+
 config BOARD_GOOGLE_QUANDISO
 	select BOARD_GOOGLE_BASEBOARD_NISSA
 	select CHROMEOS_WIFI_SAR if CHROMEOS
@@ -713,6 +716,7 @@
 	default "Bujia" if BOARD_GOOGLE_BUJIA
 	default "Tivviks" if BOARD_GOOGLE_TIVVIKS
 	default "Yavista" if BOARD_GOOGLE_YAVISTA
+	default "Sundance" if BOARD_GOOGLE_SUNDANCE
 
 config VARIANT_DIR
 	default "brya0" if BOARD_GOOGLE_BRYA0
@@ -772,6 +776,7 @@
 	default "bujia" if BOARD_GOOGLE_BUJIA
 	default "nivviks" if BOARD_GOOGLE_TIVVIKS
 	default "yavista" if BOARD_GOOGLE_YAVISTA
+	default "sundance" if BOARD_GOOGLE_SUNDANCE
 
 config VBOOT
 	select VBOOT_EARLY_EC_SYNC if !BOARD_GOOGLE_BASEBOARD_NISSA