kconfig: remove const qualifier from str_get()

update_text() apparently edits the buffer returned by str_get().
(and there is no reason why it shouldn't)

Remove 'const' quailifier and casting.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/lkc.h

@@ -76,7 +76,7 @@ struct gstr str_new(void);
 void str_free(struct gstr *gs);
 void str_append(struct gstr *gs, const char *s);
 void str_printf(struct gstr *gs, const char *fmt, ...);
-const char *str_get(struct gstr *gs);
+char *str_get(struct gstr *gs);
 
 /* menu.c */
 void _menu_init(void);

scripts/kconfig/mconf.c

@@ -440,8 +440,8 @@ static void search_conf(void)
 
 		res = get_relations_str(sym_arr, &head);
 		set_subtitle();
-		dres = show_textbox_ext("Search Results", (char *)
-					str_get(&res), 0, 0, keys, &vscroll,
+		dres = show_textbox_ext("Search Results", str_get(&res), 0, 0,
+					keys, &vscroll,
 					&hscroll, &update_text, (void *)
 					&data);
 		again = false;

scripts/kconfig/util.c

@@ -74,7 +74,7 @@ void str_printf(struct gstr *gs, const char *fmt, ...)
 }
 
 /* Retrieve value of growable string */
-const char *str_get(struct gstr *gs)
+char *str_get(struct gstr *gs)
 {
 	return gs->s;
 }