mb/google/fizz: Prepare sharing directory for variants

Clean up Kconfig file in order to support variants for fizz. Add
BOARD_GOOGLE_BASEBOARD_FIZZ that can be set by various fizz variants
to use the common baseboard configs.

BUG=b:117066935
BRANCH=Fizz
TEST=emerge-fizz coreboot

Change-Id: I9c89f1dc526a9d623e1ae4d4b52a923489b389d3
Signed-off-by: David Wu <david_wu@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/28959
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/mainboard/google/fizz/Kconfig

@@ -1,7 +1,6 @@
-if BOARD_GOOGLE_FIZZ
 
-config BOARD_SPECIFIC_OPTIONS
-	def_bool y
+config BOARD_GOOGLE_BASEBOARD_FIZZ
+	def_bool n
 	select BOARD_ROMSIZE_KB_16384
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_SPI_ACPI
@@ -24,6 +23,8 @@ config BOARD_SPECIFIC_OPTIONS
 	select RT8168_SET_LED_MODE
 	select SPD_READ_BY_WORD
 
+if BOARD_GOOGLE_BASEBOARD_FIZZ
+
 config VBOOT
 	select EC_GOOGLE_CHROMEEC_SWITCHES
 	select VBOOT_EC_EFS
@@ -37,7 +38,7 @@ config DRIVER_TPM_SPI_BUS
 config GBB_HWID
 	string
 	depends on CHROMEOS
-	default "FIZZ TEST 5997"
+	default "FIZZ TEST 5997" if BOARD_GOOGLE_FIZZ
 
 config MAINBOARD_DIR
 	string
@@ -45,11 +46,11 @@ config MAINBOARD_DIR
 
 config MAINBOARD_PART_NUMBER
 	string
-	default "Fizz"
+	default "Fizz" if BOARD_GOOGLE_FIZZ
 
 config MAINBOARD_FAMILY
 	string
-	default "Google_Fizz"
+	default "Google_Fizz" if BOARD_GOOGLE_FIZZ
 
 config MAX_CPUS
 	int
@@ -71,4 +72,4 @@ config INCLUDE_NHLT_BLOBS
 	bool "Include blobs for audio."
 	select NHLT_RT5663
 
-endif
+endif # BOARD_GOOGLE_BASEBOARD_FIZZ

src/mainboard/google/fizz/Kconfig.name

@@ -1,2 +1,3 @@
 config BOARD_GOOGLE_FIZZ
 	bool "Fizz"
+	select BOARD_GOOGLE_BASEBOARD_FIZZ