target/riscv/cpu.c: handle TCG bits of riscv_cpu_dump_state

riscv_dump_csr() is a TCG only function but we'll have to implement it at some capacity for KVM eventually, therefore put it under a CONFIG_TCG ifdef while making a note that this function is unimplemented in KVM. The csr_ops array is also TCG specific, thus the for loop inside dump_state that iterates it is also TCG only business. Signed-off-by: Daniel Henrique Barboza <daniel.barboza@oss.qualcomm.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com> Message-ID: <20260703180538.3346781-16-daniel.barboza@oss.qualcomm.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>