media: mtk-vcodec: fix error return code in vdec_vp9_decode()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: dea42fb79f ("media: mtk-vcodec: reset segment data then trig decoder")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/mtk-vcodec/vdec/vdec_vp9_if.c

@@ -890,7 +890,8 @@ static int vdec_vp9_decode(void *h_vdec, struct mtk_vcodec_mem *bs,
 			memset(inst->seg_id_buf.va, 0, inst->seg_id_buf.size);
 
 			if (vsi->show_frame & BIT(2)) {
-				if (vpu_dec_start(&inst->vpu, NULL, 0)) {
+				ret = vpu_dec_start(&inst->vpu, NULL, 0);
+				if (ret) {
 					mtk_vcodec_err(inst, "vpu trig decoder failed");
 					goto DECODE_ERROR;
 				}