mb/kontron/bsl6: 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 kontron/boxer26 with BUILD_TIMELESS=1, coreboot.rom remains the
same.

Change-Id: I08bd68aa2f98f93b8c5daf1ab2f3c1bbce521c53
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49061
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/mainboard/kontron/bsl6/Kconfig

@@ -1,15 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-if BOARD_KONTRON_BSL6 || BOARD_SIEMENS_BOXER26
-
-config BOARD_SPECIFIC_OPTIONS
-	def_bool y
+config BOARD_KONTRON_BSL6_COMMON
+	def_bool n
 	select BOARD_ROMSIZE_KB_16384
 	select SOC_INTEL_SKYLAKE
 	select SKYLAKE_SOC_PCH_H
 	select EXCLUDE_NATIVE_SD_INTERFACE
 	select NO_FADT_8042
-	select HAVE_ACPI_RESUME if BOARD_KONTRON_BSL6
 	select HAVE_ACPI_TABLES
 	select HAVE_OPTION_TABLE
 	select HAVE_CMOS_DEFAULT
@@ -17,8 +14,19 @@ config BOARD_SPECIFIC_OPTIONS
 	select EC_KONTRON_KEMPLD
 	select MAINBOARD_HAS_LIBGFXINIT
 	select DRIVERS_I2C_NCT7802Y
-	select DRIVERS_I2C_LM96000 if BOARD_SIEMENS_BOXER26
-	select SECUNET_DMI if BOARD_SIEMENS_BOXER26
+
+config BOARD_KONTRON_BSL6_OPTIONS
+	bool
+	select BOARD_KONTRON_BSL6_COMMON
+	select HAVE_ACPI_RESUME
+
+config BOARD_KONTRON_BOXER26_OPTIONS
+	bool
+	select BOARD_KONTRON_BSL6_COMMON
+	select DRIVERS_I2C_LM96000
+	select SECUNET_DMI
+
+if BOARD_KONTRON_BSL6_COMMON
 
 config MAINBOARD_DIR
 	string

src/mainboard/kontron/bsl6/Kconfig.name

@@ -1,5 +1,7 @@
 config BOARD_KONTRON_BSL6
 	bool "COMe-bSL6"
+	select BOARD_KONTRON_BSL6_OPTIONS
 
 config BOARD_SIEMENS_BOXER26
 	bool "COMe-bSL6 on Siemens/Boxer26"
+	select BOARD_KONTRON_BOXER26_OPTIONS