mtd: core: fix nvmem error reporting

The master MTD will only have an associated device if
CONFIG_MTD_PARTITIONED_MASTER is set, thus we cannot use dev_err() on
mtd->dev. Instead use the parent device which is the physical flash
memory.

Fixes: 4b361cf ("mtd: core: add OTP nvmem provider support")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230308082021.870459-2-michael@walle.cc

Author: mwalle

drivers/mtd/mtdcore.c

@@ -939,6 +939,7 @@ static int mtd_nvmem_fact_otp_reg_read(void *priv, unsigned int offset,
 
 static int mtd_otp_nvmem_add(struct mtd_info *mtd)
 {
+	struct device *dev = mtd->dev.parent;
 	struct nvmem_device *nvmem;
 	ssize_t size;
 	int err;
@@ -952,7 +953,7 @@ static int mtd_otp_nvmem_add(struct mtd_info *mtd)
 			nvmem = mtd_otp_nvmem_register(mtd, "user-otp", size,
 						       mtd_nvmem_user_otp_reg_read);
 			if (IS_ERR(nvmem)) {
-				dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n");
+				dev_err(dev, "Failed to register OTP NVMEM device\n");
 				return PTR_ERR(nvmem);
 			}
 			mtd->otp_user_nvmem = nvmem;
@@ -970,7 +971,7 @@ static int mtd_otp_nvmem_add(struct mtd_info *mtd)
 			nvmem = mtd_otp_nvmem_register(mtd, "factory-otp", size,
 						       mtd_nvmem_fact_otp_reg_read);
 			if (IS_ERR(nvmem)) {
-				dev_err(&mtd->dev, "Failed to register OTP NVMEM device\n");
+				dev_err(dev, "Failed to register OTP NVMEM device\n");
 				err = PTR_ERR(nvmem);
 				goto err;
 			}