target/riscv: Add Shakti C class CPU

target/riscv: Add Shakti C class CPU

C-Class is a member of the SHAKTI family of processors from IIT-M.

It is an extremely configurable and commercial-grade 5-stage in-order
core supporting the standard RV64GCSUN ISA extensions.

Signed-off-by: Vijai Kumar K <vijai@behindbytes.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210401181457.73039-2-vijai@behindbytes.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>