This board uses Gowin GW2AR series chip (which is GW2A with integrated
RAM).
Support for the integrated SDRAM on Tang Nano 20K is still TODO.
Note: currently when the SD card is enabled, block 0 could be correctly
read but block 1 will fail.
Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Icenowy Zheng