riscv: dts: spacemit: add Banana Pi BPI-F3 board device tree

riscv: dts: spacemit: add Banana Pi BPI-F3 board device tree

Banana Pi BPI-F3 [1] is a industrial grade RISC-V development board, it
design with SpacemiT K1 8 core RISC-V chip [2].

Currently only support booting into console with only uart enabled,
other features will be added soon later.

Link: https://docs.banana-pi.org/en/BPI-F3/BananaPi_BPI-F3
Link: https://www.spacemit.com/en/spacemit-key-stone-2/
Signed-off-by: Yangyu Chen <cyy@cyyself.name>
Acked-by: Jesse Taube <jesse@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Yixun Lan <dlan@gentoo.org>