media: mtk-vcodec: potential dereference of null pointer

The return value of devm_kzalloc() needs to be checked.
To avoid use of null pointer in case of thefailure of alloc.

Fixes: 46233e91fa ("media: mtk-vcodec: move firmware implementations into their own files")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/platform/mtk-vcodec/mtk_vcodec_fw_vpu.c

@@ -102,6 +102,8 @@ struct mtk_vcodec_fw *mtk_vcodec_fw_vpu_init(struct mtk_vcodec_dev *dev,
 	vpu_wdt_reg_handler(fw_pdev, mtk_vcodec_vpu_reset_handler, dev, rst_id);
 
 	fw = devm_kzalloc(&dev->plat_dev->dev, sizeof(*fw), GFP_KERNEL);
+	if (!fw)
+		return ERR_PTR(-ENOMEM);
 	fw->type = VPU;
 	fw->ops = &mtk_vcodec_vpu_msg;
 	fw->pdev = fw_pdev;