media: intel/ipu6: Fix a null pointer dereference in ipu6_isys_query_stream_by_source

stream is NULL when source is less than 0 in
ipu6_isys_query_stream_by_source. It's a null pointer dereference.

Actually, this should be isys->adev->auxdev.dev.

Fixes: 3c1dfb5a ("media: intel/ipu6: input system video nodes and buffer queues")
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/pci/intel/ipu6/ipu6-isys-video.c

@@ -943,7 +943,7 @@ ipu6_isys_query_stream_by_source(struct ipu6_isys *isys, int source, u8 vc)
 		return NULL;
 
 	if (source < 0) {
-		dev_err(&stream->isys->adev->auxdev.dev,
+		dev_err(&isys->adev->auxdev.dev,
 			"query stream with invalid port number\n");
 		return NULL;
 	}