cmd: eeprom: Hide eeprom layout versioning behind a Kconfig option

Add a new Kconfig option EEPROM_LAYOUT_VERSIONS, and hide eeprom
layout versionsing code behind it. Only print the relevant help in
'eeprom' command usage if this option is enabled.

Enable this new option for cm_fx6_defconfig and cm_t43_defconfig.
These are the only boards using EEPROM layout versioning.

Signed-off-by: Marek BehĂșn <kabel@kernel.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index b026439..8c37099 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -803,9 +803,16 @@
 			types of eeprom fields. Can be used for defining
 			custom layouts.
 
+config EEPROM_LAYOUT_VERSIONS
+	bool "Support specifying eeprom layout version"
+	depends on CMD_EEPROM_LAYOUT
+	help
+	  Support specifying eeprom layout version in the 'eeprom' command
+	  via the -l option.
+
 config EEPROM_LAYOUT_HELP_STRING
 	  string "Tells user what layout names are supported"
-	  depends on CMD_EEPROM_LAYOUT
+	  depends on EEPROM_LAYOUT_VERSIONS
 	  default "<not defined>"
 	  help
 	    Help printed with the LAYOUT VERSIONS part of the 'eeprom'