media: mediatek: vcodec: Fix a reference leak in mtk_vcodec_fw_vpu_init()

vpu_get_plat_device() increases the reference count of the returned
platform device. However, when devm_kzalloc() fails, the reference
is not released, causing a reference leak.

Fix this by calling put_device() on fw_pdev->dev before returning
on the error path.

Fixes: e25a89f743b1 ("media: mtk-vcodec: potential dereference of null pointer")
Cc: [e-mail]
Signed-off-by: Haoxiang Li <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Reviewed-by: Tzung-Bi Shih <[e-mail]>
Signed-off-by: Nicolas Dufresne <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

drivers/media/platform/mediatek/vcodec/common/mtk_vcodec_fw_vpu.c

···
 		vpu_wdt_reg_handler(fw_pdev, mtk_vcodec_vpu_reset_enc_handler, priv, rst_id);
 
 	fw = devm_kzalloc(&plat_dev->dev, sizeof(*fw), GFP_KERNEL);
-	if (!fw)
+	if (!fw) {
+		put_device(&fw_pdev->dev);
 		return ERR_PTR(-ENOMEM);
+	}
 	fw->type = VPU;
 	fw->ops = &mtk_vcodec_vpu_msg;
 	fw->pdev = fw_pdev;