media: sun6i-isp: proc: Error out on invalid port to fix warning

The enabled variable is only set for a valid port and used later,
which triggers an uninitialized use smatch warning. Explicitly error
out in that case to fix the warning.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Fixes: e3185e1d ("media: staging: media: Add support for the Allwinner A31 ISP")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/staging/media/sunxi/sun6i-isp/sun6i_isp_proc.c

@@ -416,7 +416,7 @@ static int sun6i_isp_proc_notifier_bound(struct v4l2_async_notifier *notifier,
 		enabled = !proc->source_csi0.expected;
 		break;
 	default:
-		break;
+		return -EINVAL;
 	}
 
 	source->subdev = remote_subdev;