doc: correct kflash settings for Maix One Dock

The correct kflash parameter value for the Maix One Dock is "dan".

See:
https://github.com/sipeed/platform-kendryte210/blob/master/boards/sipeed-maix-one-dock.json#L22

Fixes: 137dc153fda9 ("doc: riscv: Update documentation for Sipeed MAIX boards")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
1 file changed