dt-bindings: riscv: cpus: Add AMD MicroBlaze V compatible

MicroBlaze V is new AMD/Xilinx soft-core 32bit RISC-V processor IP.
It is hardware compatible with classic MicroBlaze processor.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/d442d916204d26f82c1c3a924a4cdfb117960e1b.1699270661.git.michal.simek@amd.com


Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>