media: cros-ec-cec: decrement HDMI device refcount

The CrosEC CEC driver never decremented the HDMI device refcount.
CEC drivers only need the HDMI device pointer as a key in the
notifier list, it never accesses the device, so there is no
need to keep a reference.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/cros-ec-cec/cros-ec-cec.c

@@ -236,6 +236,7 @@ static int cros_ec_cec_get_notifier(struct device *dev,
 				return -EPROBE_DEFER;
 
 			*notify = cec_notifier_get_conn(d, m->conn);
+			put_device(d);
 			return 0;
 		}
 	}