mb/clevo/cml-u: Rework Kconfig

Rework Kconfig file so that each variant has its own config option with
their specific selects / configuration and move common selects to a
seperate config option, which is used as base for each variant.

Built clevo/l140cu with BUILD_TIMELESS=1, coreboot.rom remains the same.

Change-Id: I1f5b6f535597149f28dd8c8322acc2e988f11505
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49025
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>

src/mainboard/clevo/cml-u/Kconfig

@@ -1,16 +1,12 @@
-if BOARD_CLEVO_L140CU
-
-config BOARD_SPECIFIC_OPTIONS
-	def_bool y
+config BOARD_CLEVO_CMLU_COMMON
+	def_bool n
 	select BOARD_ROMSIZE_KB_16384
 	select DRIVERS_I2C_HID
-	select EC_SYSTEM76_EC
 	select HAVE_ACPI_RESUME
 	select HAVE_ACPI_TABLES
 	select HAVE_CMOS_DEFAULT
 	select HAVE_OPTION_TABLE
 	select HAVE_SMI_HANDLER
-	select HAVE_SPD_IN_CBFS
 	select INTEL_GMA_HAVE_VBT
 	select INTEL_LPSS_UART_FOR_CONSOLE
 	select MAINBOARD_HAS_LIBGFXINIT
@@ -22,6 +18,14 @@ config BOARD_SPECIFIC_OPTIONS
 	select SPD_READ_BY_WORD
 	select SYSTEM_TYPE_LAPTOP
 
+config BOARD_CLEVO_L140CU_OPTIONS
+	bool
+	select BOARD_CLEVO_CMLU_COMMON
+	select EC_SYSTEM76_EC
+	select HAVE_SPD_IN_CBFS
+
+if BOARD_CLEVO_CMLU_COMMON
+
 config MAINBOARD_DIR
 	string
 	default "clevo/cml-u"

src/mainboard/clevo/cml-u/Kconfig.name

@@ -2,3 +2,4 @@ comment "Comet Lake U"
 
 config BOARD_CLEVO_L140CU
 	bool "L140CU / L141CU"
+	select BOARD_CLEVO_L140CU_OPTIONS