sh: Convert the last use of 'optional' property in Kconfig

The 'choice' statement is primarily used to exclusively select one
option, but the 'optional' property allows all entries to be disabled.

This feature is rarely used. In fact, it is only used in arch/sh/Kconfig
because the equivalent outcome can be achieved by inserting one more
entry.

The 'optional' property support will be removed from Kconfig.

This commit replaces the 'optional' property with a dummy option,
CMDLINE_FROM_BOOTLOADER, as seen in some other architectures.

Note:
 The 'default CMDLINE_OVERWRITE' statement does not work as intended
 in combination with 'optional'. If neither CONFIG_CMDLINE_OVERWRITE
 nor CONFIG_CMDLINE_EXTEND is specified in a defconfig file, both of
 them are disabled. This is a bug. To maintain the current behavior,
 I added CONFIG_CMDLINE_FROM_BOOTLOADER=y to those defconfig files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

Author: masahir0y

arch/sh/Kconfig

@@ -709,7 +709,6 @@ config ROMIMAGE_MMCIF
 
 choice
 	prompt "Kernel command line"
-	optional
 	default CMDLINE_OVERWRITE
 	help
 	  Setting this option allows the kernel command line arguments
@@ -727,6 +726,11 @@ config CMDLINE_EXTEND
 	  Given string will be concatenated with arguments passed in
 	  by a bootloader.
 
+config CMDLINE_FROM_BOOTLOADER
+	bool "Use bootloader kernel arguments"
+	help
+	  Uses the command-line options passed by the boot loader.
+
 endchoice
 
 config CMDLINE

arch/sh/configs/apsh4a3a_defconfig

@@ -15,6 +15,7 @@ CONFIG_MEMORY_START=0x0C000000
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_SH_STORE_QUEUES=y
 CONFIG_SH_APSH4A3A=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_HIGH_RES_TIMERS=y
 CONFIG_KEXEC=y
 CONFIG_PREEMPT=y

arch/sh/configs/apsh4ad0a_defconfig

@@ -42,6 +42,7 @@ CONFIG_SECCOMP=y
 CONFIG_PREEMPT=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_BINFMT_MISC=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_PM=y
 CONFIG_PM_DEBUG=y
 CONFIG_PM=y

arch/sh/configs/edosk7705_defconfig

@@ -19,6 +19,7 @@
 CONFIG_CPU_SUBTYPE_SH7705=y
 CONFIG_SH_EDOSK7705=y
 CONFIG_SH_PCLK_FREQ=31250000
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 # CONFIG_PREVENT_FIRMWARE_BUILD is not set
 # CONFIG_INPUT is not set
 # CONFIG_SERIO is not set

arch/sh/configs/hp6xx_defconfig

@@ -15,6 +15,7 @@ CONFIG_SH_DMA_API=y
 CONFIG_HD64461_ENABLER=y
 CONFIG_PCCARD=y
 CONFIG_PM=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_APM_EMULATION=y
 # CONFIG_STANDALONE is not set
 CONFIG_BLK_DEV_SD=y

arch/sh/configs/landisk_defconfig

@@ -15,6 +15,7 @@ CONFIG_KEXEC=y
 CONFIG_PCI=y
 CONFIG_PCCARD=y
 CONFIG_YENTA=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y

arch/sh/configs/magicpanelr2_defconfig

@@ -22,6 +22,7 @@ CONFIG_SH_PCLK_FREQ=24000000
 CONFIG_SH_DMA=y
 CONFIG_SH_DMA_API=y
 CONFIG_HEARTBEAT=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_NET=y
 CONFIG_PACKET=y
 CONFIG_UNIX=y

arch/sh/configs/rsk7264_defconfig

@@ -21,6 +21,7 @@ CONFIG_MEMORY_START=0x0c000000
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_SH_RSK=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 # CONFIG_SH_TIMER_MTU2 is not set
 CONFIG_BINFMT_FLAT=y
 CONFIG_NET=y

arch/sh/configs/rsk7269_defconfig

@@ -10,6 +10,7 @@ CONFIG_MEMORY_SIZE=0x02000000
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_SH_RSK=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 # CONFIG_SH_TIMER_MTU2 is not set
 CONFIG_SH_PCLK_FREQ=66700000
 CONFIG_BINFMT_FLAT=y

arch/sh/configs/se7619_defconfig

@@ -14,6 +14,7 @@ CONFIG_FLATMEM_MANUAL=y
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_SH_7619_SOLUTION_ENGINE=y
 CONFIG_HZ_100=y
+CONFIG_CMDLINE_FROM_BOOTLOADER=y
 CONFIG_BINFMT_FLAT=y
 CONFIG_BINFMT_ZFLAT=y
 # CONFIG_STANDALONE is not set