media: mediatek: vcodec: Use ctx vb2_queue mutex instead of device mutex

There is only one device mutex to lock vb2_queue when running
multi-instance encoding, it can be set by each encoder context.

[hverkuil: fix q_mutex documentation in the header]

Signed-off-by: Irui Wang <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h

···
  * @hw_id: hardware index used to identify different hardware.
  *
  * @msg_queue: msg queue used to store lat buffer information.
+ * @q_mutex: vb2_queue mutex.
  */
 struct mtk_vcodec_ctx {
 	enum mtk_instance_type type;
···
 	int hw_id;
 
 	struct vdec_msg_queue msg_queue;
+
+	struct mutex q_mutex;
 };
 
 /*

drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c

···
 {
 	struct mtk_q_data *q_data;
 
-	ctx->m2m_ctx->q_lock = &ctx->dev->dev_mutex;
+	ctx->m2m_ctx->q_lock = &ctx->q_mutex;
 	ctx->fh.m2m_ctx = ctx->m2m_ctx;
 	ctx->fh.ctrl_handler = &ctx->ctrl_hdl;
 	INIT_WORK(&ctx->encode_work, mtk_venc_worker);
···
 	src_vq->ops		= &mtk_venc_vb2_ops;
 	src_vq->mem_ops		= &vb2_dma_contig_memops;
 	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
-	src_vq->lock		= &ctx->dev->dev_mutex;
+	src_vq->lock		= &ctx->q_mutex;
 	src_vq->dev		= &ctx->dev->plat_dev->dev;
 
 	ret = vb2_queue_init(src_vq);
···
 	dst_vq->ops		= &mtk_venc_vb2_ops;
 	dst_vq->mem_ops		= &vb2_dma_contig_memops;
 	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
-	dst_vq->lock		= &ctx->dev->dev_mutex;
+	dst_vq->lock		= &ctx->q_mutex;
 	dst_vq->dev		= &ctx->dev->plat_dev->dev;
 
 	return vb2_queue_init(dst_vq);

drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc_drv.c

···
 	INIT_LIST_HEAD(&ctx->list);
 	ctx->dev = dev;
 	init_waitqueue_head(&ctx->queue[0]);
+	mutex_init(&ctx->q_mutex);
 
 	ctx->type = MTK_INST_ENCODER;
 	ret = mtk_vcodec_enc_ctrls_setup(ctx);