Input: hp_sdc - use del_timer_sync() in exit path

Make sure that no callback is running before we teardown the module.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/serio/hp_sdc.c

@@ -984,7 +984,7 @@ static void hp_sdc_exit(void)
 	free_irq(hp_sdc.irq, &hp_sdc);
 	write_unlock_irq(&hp_sdc.lock);
 
-	del_timer(&hp_sdc.kicker);
+	del_timer_sync(&hp_sdc.kicker);
 
 	tasklet_kill(&hp_sdc.task);