CRS305-1G-4S has a switch chip with an integrated CPU (98DX3236) and
like some of the other similar boards requires bin_hdr.
bin_hdr (DDR3 init stage) is currently retrieved from the stock
bootloader and compiled into the kwb image.
Adds support for U-Boot, enable UART, SPI, Winbond SPI flash chip
support and writing env to SPI flash.
Signed-off-by: Luka Kovacic
Reviewed-by: Chris Packham
Reviewed-by: Stefan Roese
Signed-off-by: Stefan Roese