kconfig: attach help text to menus

Roman Zippel wrote:
> A simple example would be
> help texts, right now they are per symbol, but they should really be per
> menu, so archs can provide different help texts for something.

This patch does this and at the same time introduce a few API
funtions used to access the help text.

The relevant api functions are introduced in the various frontends.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h
index 1503077..4d09f6d 100644
--- a/scripts/kconfig/lkc_proto.h
+++ b/scripts/kconfig/lkc_proto.h
@@ -15,6 +15,8 @@
 P(menu_get_prompt,const char *,(struct menu *menu));
 P(menu_get_root_menu,struct menu *,(struct menu *menu));
 P(menu_get_parent_menu,struct menu *,(struct menu *menu));
+P(menu_has_help,bool,(struct menu *menu));
+P(menu_get_help,const char *,(struct menu *menu));
 
 /* symbol.c */
 P(symbol_hash,struct symbol *,[SYMBOL_HASHSIZE]);