mtd: spi-nor: Reset SPI_MASTER_U_PAGE flag after chip erase operation

In stacked mode, by default SPI_MASTER_U_PAGE flag is reset, this ensures
that the lower flash device is selected by default. For performing any
operation on the upper flash the driver sets the SPI_MASTER_U_PAGE flag,
performs the operation and then resets SPI_MASTER_U_PAGE flag. But during
chip erase operation, after erasing the upper flash the driver doesn't
reset the SPI_MASTER_U_PAGE flag before exiting. This is not inline
with the default behaviours. This patch fixes the issue by resetting the
SPI_MASTER_U_PAGE flag before exiting spi_nor_erase_chip() api.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>

drivers/mtd/spi-nor/core.c

@@ -1281,8 +1281,8 @@ static int spi_nor_erase_chip(struct spi_nor *nor)
 				return ret;
 			nor->spimem->spi->master->flags |= SPI_MASTER_U_PAGE;
 			ret = spi_mem_exec_op(nor->spimem, &op);
+			nor->spimem->spi->master->flags &= ~SPI_MASTER_U_PAGE;
 		}
-		return ret;
 	} else {
 		ret = spi_nor_controller_ops_write_reg(nor,
 						       SPINOR_OP_CHIP_ERASE,