Add document for Banana Pi F3 board which based on SpacemiT's K1 SoC.
Signed-off-by: Kongyang Liu <seashell11234455@gmail.com>
Signed-off-by: Huan Zhou <pericycle.cc@gmail.com>
Tested-by: Marcel Ziswiler <marcel@ziswiler.com>
Reviewed-by: Yixun Lan <dlan@gentoo.org>
