mtd: nand: mtk: release lock on error path

We only want to hold the lock on the success path, not this error path.

Fixes: 7ec4a37c ("mtd: nand: mediatek: add support for different MTK NAND FLASH Controller IP")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/mtk_ecc.c

@@ -273,8 +273,10 @@ int mtk_ecc_enable(struct mtk_ecc *ecc, struct mtk_ecc_config *config)
 	mtk_ecc_wait_idle(ecc, op);
 
 	ret = mtk_ecc_config(ecc, config);
-	if (ret)
+	if (ret) {
+		mutex_unlock(&ecc->lock);
 		return ret;
+	}
 
 	if (config->mode != ECC_NFI_MODE || op != ECC_ENCODE) {
 		init_completion(&ecc->done);