[settings] Expose find_child_settings()

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/settings.c

  * @v name		Name within this parent
  * @ret settings	Settings block, or NULL
  */
-static struct settings * find_child_settings ( struct settings *parent,
-					       const char *name ) {
+struct settings * find_child_settings ( struct settings *parent,
+					const char *name ) {
 	struct settings *settings;
 
 	/* Treat empty name as meaning "this block" */

src/include/ipxe/settings.h

 extern void clear_settings ( struct settings *settings );
 extern int setting_cmp ( struct setting *a, struct setting *b );
 
+extern struct settings * find_child_settings ( struct settings *parent,
+					       const char *name );
 extern const char * settings_name ( struct settings *settings );
 extern struct settings * find_settings ( const char *name );
 extern struct setting * find_setting ( const char *name );