[media] saa6588: after calling CMD_CLOSE, CMD_POLL is broken

CMD_CLOSE sets data_available_for_read to 1, which is necessary to do the
wakeup call, but it is never reset to 0.

Because of this calling CMD_POLL afterwards will always return that data is
available, even if there isn't any.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/i2c/saa6588.c

@@ -402,6 +402,7 @@ static long saa6588_ioctl(struct v4l2_subdev *sd, unsigned int cmd, void *arg)
 	case SAA6588_CMD_CLOSE:
 		s->data_available_for_read = 1;
 		wake_up_interruptible(&s->read_queue);
+		s->data_available_for_read = 0;
 		a->result = 0;
 		break;
 		/* --- read() for /dev/radio --- */