mtd: spi-nor: core: Advance erase after the erase cmd has been completed

addr and len were gratuitously updated even when spi_nor_wait_till_ready()
failed. Wait for the erase cmd to complete and then advance the erase.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20210306095002.22983-2-tudor.ambarus@microchip.com

drivers/mtd/spi-nor/core.c

@@ -1618,12 +1618,12 @@ static int spi_nor_erase_multi_sectors(struct spi_nor *nor, u64 addr, u32 len)
 			if (ret)
 				goto destroy_erase_cmd_list;
 
-			addr += cmd->size;
-			cmd->count--;
-
 			ret = spi_nor_wait_till_ready(nor);
 			if (ret)
 				goto destroy_erase_cmd_list;
+
+			addr += cmd->size;
+			cmd->count--;
 		}
 		list_del(&cmd->list);
 		kfree(cmd);
@@ -1704,12 +1704,12 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 			if (ret)
 				goto erase_err;
 
-			addr += mtd->erasesize;
-			len -= mtd->erasesize;
-
 			ret = spi_nor_wait_till_ready(nor);
 			if (ret)
 				goto erase_err;
+
+			addr += mtd->erasesize;
+			len -= mtd->erasesize;
 		}
 
 	/* erase multiple sectors */