timer: Export destroy_hrtimer_on_stack()

hrtimer_init_on_stack() needs a matching call to
destroy_hrtimer_on_stack(), so both need to be exported.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/time/hrtimer.c

@@ -425,6 +425,7 @@ void destroy_hrtimer_on_stack(struct hrtimer *timer)
 {
 	debug_object_free(timer, &hrtimer_debug_descr);
 }
+EXPORT_SYMBOL_GPL(destroy_hrtimer_on_stack);
 
 #else
 static inline void debug_hrtimer_init(struct hrtimer *timer) { }