Kconfig: Introduce USE_BOOTCOMMAND and migrate BOOTCOMMAND

We first introduce CONFIG_USE_BOOTCOMMAND, similar to
CONFIG_USE_BOOTARGS.  We then migrate CONFIG_BOOTCOMMAND for most
CONFIG_DISTRO_DEFAULT users.  In some cases platforms have a complex
scheme around this usage, and these have been defered for the moment so
that platform maintainers can work on a migration plan.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/common/Kconfig b/common/Kconfig
index f96a25f..c50d6eb 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -200,6 +200,23 @@
 	  CONFIG_BOOTARGS goes into the environment value "bootargs". Note that
 	  this value will also override the "chosen" node in FDT blob.
 
+config USE_BOOTCOMMAND
+	bool "Enable a default value for bootcmd"
+	help
+	  Provide a default value for the bootcmd entry in the environment.  If
+	  autoboot is enabled this is what will be run automatically.  Enable
+	  this option to be able to specify CONFIG_BOOTCOMMAND as a string.  If
+	  this option is disabled, CONFIG_BOOTCOMMAND will be undefined and
+	  won't take any space in U-Boot image.
+
+config BOOTCOMMAND
+	string "bootcmd value"
+	depends on USE_BOOTCOMMAND
+	default "run distro_bootcmd" if DISTRO_DEFAULTS
+	help
+	  This is the string of commands that will be used as bootcmd and if
+	  AUTOBOOT is set, automatically run.
+
 menu "Console"
 
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