[media] media: vb2: correct queue initialization order

q->memory entry is initialized to late, so if allocation of memory buffers
fails, the buffers might not be freed correctly (q->memory is tested in
__vb2_free_mem, which can be called before setting q->memory).
Reported-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf2-core.c

@@ -525,6 +525,7 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 	num_buffers = min_t(unsigned int, req->count, VIDEO_MAX_FRAME);
 	memset(plane_sizes, 0, sizeof(plane_sizes));
 	memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
+	q->memory = req->memory;
 
 	/*
 	 * Ask the driver how many buffers and planes per buffer it requires.
@@ -566,8 +567,6 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 		ret = num_buffers;
 	}
 
-	q->memory = req->memory;
-
 	/*
 	 * Return the number of successfully allocated buffers
 	 * to the userspace.