[media] radio-keene: add delay in order to settle hardware

It was found by trial and error testing that at least 11 ms delay is
needed before first I/O, otherwise device will skip given command.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/radio-keene.c

@@ -382,6 +382,8 @@ static int usb_keene_probe(struct usb_interface *intf,
 	video_set_drvdata(&radio->vdev, radio);
 	set_bit(V4L2_FL_USE_FH_PRIO, &radio->vdev.flags);
 
+	/* at least 11ms is needed in order to settle hardware */
+	msleep(20);
 	keene_cmd_main(radio, 95.16 * FREQ_MUL, false);
 
 	retval = video_register_device(&radio->vdev, VFL_TYPE_RADIO, -1);