mtd: spi-nor: Fix an error code in spi_nor_read_raw()

The problem is that if "ret" is negative then when we check if
"ret > len", that condition is going to be true because of type
promotion.  So this patch re-orders the code to check for negatives
first and preserve those error codes.

Fixes: f384b352cb ("mtd: spi-nor: parse Serial Flash Discoverable Parameters (SFDP) tables")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

drivers/mtd/spi-nor/spi-nor.c

@@ -2907,10 +2907,10 @@ static int spi_nor_read_raw(struct spi_nor *nor, u32 addr, size_t len, u8 *buf)
 
 	while (len) {
 		ret = spi_nor_read_data(nor, addr, len, buf);
-		if (!ret || ret > len)
-			return -EIO;
 		if (ret < 0)
 			return ret;
+		if (!ret || ret > len)
+			return -EIO;
 
 		buf += ret;
 		addr += ret;