media: sh_veu: Correct return type for mem2mem buffer helpers

Fix the assigned type of mem2mem buffer handling API.
Namely, these functions:

 v4l2_m2m_next_buf
 v4l2_m2m_last_buf
 v4l2_m2m_buf_remove
 v4l2_m2m_next_src_buf
 v4l2_m2m_next_dst_buf
 v4l2_m2m_last_src_buf
 v4l2_m2m_last_dst_buf
 v4l2_m2m_src_buf_remove
 v4l2_m2m_dst_buf_remove

return a struct vb2_v4l2_buffer, and not a struct vb2_buffer.

Fixing this is necessary to fix the mem2mem buffer handling API,
changing the return to the correct struct vb2_v4l2_buffer instead
of a void pointer.
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/sh_veu.c

@@ -273,13 +273,13 @@ static void sh_veu_process(struct sh_veu_dev *veu,
 static void sh_veu_device_run(void *priv)
 {
 	struct sh_veu_dev *veu = priv;
-	struct vb2_buffer *src_buf, *dst_buf;
+	struct vb2_v4l2_buffer *src_buf, *dst_buf;
 
 	src_buf = v4l2_m2m_next_src_buf(veu->m2m_ctx);
 	dst_buf = v4l2_m2m_next_dst_buf(veu->m2m_ctx);
 
 	if (src_buf && dst_buf)
-		sh_veu_process(veu, src_buf, dst_buf);
+		sh_veu_process(veu, &src_buf->vb2_buf, &dst_buf->vb2_buf);
 }
 
 		/* ========== video ioctls ========== */