Update At91Bootstrap to 4.0.1 2021

Hello Together,

I have successfully able to update to new version of bootstrap and u-boot.

Here is the process for updating Bootstrap.

1. Add support for the DDR RAM. Enable 64MB RAM configuration and chip W9751G6KB

2. Update the defconfig as per the board configurations

For Nor Flash: rugged_board_a5d2xqspi_uboot_defconfig

For SD Card: rugged_board_a5d2xsd1_uboot_defconfig

GitHub - jagannath-sahoo/at91bootstrap: Second level bootloader for Microchip SoC (aka AT91)

Branch: at91bootstrap4-rba5d2x