kconfig: Remove unnecessary prototypes from headers

Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 72c9dba..b05cc3d 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -125,7 +125,7 @@
 		sym_type_name(sym->type), sym_type_name(type));
 }
 
-struct property *menu_add_prop(enum prop_type type, char *prompt, struct expr *expr, struct expr *dep)
+static struct property *menu_add_prop(enum prop_type type, char *prompt, struct expr *expr, struct expr *dep)
 {
 	struct property *prop = prop_alloc(type, current_entry->sym);
 
@@ -615,7 +615,7 @@
 /*
  * head is optional and may be NULL
  */
-void get_symbol_str(struct gstr *r, struct symbol *sym,
+static void get_symbol_str(struct gstr *r, struct symbol *sym,
 		    struct list_head *head)
 {
 	bool hit;