media/video: don't use flush_scheduled_work()

This patch converts the remaining users of flush_scheduled_work() in
media/video.

* bttv-input.c and cx23885-input.c don't use workqueue at all.  No
  need to flush.

* Make omap24xxcam.c and saa7134-empress.c flush the used work
  directly.

* In fd_defio.c, replace cancel_delayed_work() +
  flush_scheduled_work() with cancel_delayed_work_sync().  While at
  it, replace the deprecated cancel_rearming_delayed_work() with
  cancel_delayed_work_sync().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/bt8xx/bttv-input.c b/drivers/media/video/bt8xx/bttv-input.c
index 6bf05a7..1989f00 100644
--- a/drivers/media/video/bt8xx/bttv-input.c
+++ b/drivers/media/video/bt8xx/bttv-input.c
@@ -229,16 +229,13 @@
 
 static void bttv_ir_stop(struct bttv *btv)
 {
-	if (btv->remote->polling) {
+	if (btv->remote->polling)
 		del_timer_sync(&btv->remote->timer);
-		flush_scheduled_work();
-	}
 
 	if (btv->remote->rc5_gpio) {
 		u32 gpio;
 
 		del_timer_sync(&btv->remote->timer_end);
-		flush_scheduled_work();
 
 		gpio = bttv_gpio_read(&btv->c);
 		bttv_gpio_write(&btv->c, gpio & ~(1 << 4));