hush: add CONFIG_HUSH_PARSER to Kconfig

The README file states that the macros beginning with "CONFIG_SYS_"
depend on the hardware etc. and should not be meddled with if you do
not what you're doing.
We have already screwed up with this policy; we have given the prefix
"CONFIG_SYS_" to many user-selectable configurations.
Here, "CONFIG_SYS_HUSH_PARSER" is one of them.  Users can enable it
if they want to use a more powerful command line parser, or disable it
if they only need a simple one.

This commit attempts to rename CONFIG_SYS_HUSH_PARSER to
CONFIG_HUSH_PARSER and move it to Kconfig.

Every board maintainer is expected to enable CONFIG_HUSH_PARSER
(= add "CONFIG_HUSH_PARSER=y" to his defconfig file) and remove
"#define CONFIG_SYS_HUSH_PARSER" from his header file.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

README

@@ -2835,18 +2835,6 @@ CBFS (Coreboot Filesystem) support
 
 		Enable auto completion of commands using TAB.
 
-		CONFIG_SYS_HUSH_PARSER
-
-		Define this variable to enable the "hush" shell (from
-		Busybox) as command line interpreter, thus enabling
-		powerful command line syntax like
-		if...then...else...fi conditionals or `&&' and '||'
-		constructs ("shell scripts").
-
-		If undefined, you get the old, much simpler behaviour
-		with a somewhat smaller memory footprint.
-
-
 		CONFIG_SYS_PROMPT_HUSH_PS2
 
 		This defines the secondary prompt string, which is

common/Kconfig

@@ -1,6 +1,23 @@
 menu "Command line interface"
 	depends on !SPL_BUILD
 
+config HUSH_PARSER
+	bool "Use hush shell"
+	select SYS_HUSH_PARSER
+	help
+	  This option enables the "hush" shell (from Busybox) as command line
+	  interpreter, thus enabling powerful command line syntax like
+	  if...then...else...fi conditionals or `&&' and '||'
+	  constructs ("shell scripts").
+
+	  If disabled, you get the old, much simpler behaviour with a somewhat
+	  smaller memory footprint.
+
+config SYS_HUSH_PARSER
+	bool
+	help
+	  Backward compatibility.
+
 config CMD_BOOTM
 	bool "Enable bootm command"
 	default y