backlight: lm3630a_bl: Remove redundant 'flush_workqueue()' calls

'destroy_workqueue()' already drains the queue before destroying it, so
there is no need to flush it explicitly.

Remove the redundant 'flush_workqueue()' calls.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/backlight/lm3630a_bl.c

@@ -594,7 +594,6 @@ static int lm3630a_remove(struct i2c_client *client)
 
 	if (pchip->irq) {
 		free_irq(pchip->irq, pchip);
-		flush_workqueue(pchip->irqthread);
 		destroy_workqueue(pchip->irqthread);
 	}
 	return 0;