target/riscv: make CPUCFG() macro public

target/riscv: make CPUCFG() macro public

The RISC-V KVM driver uses a CPUCFG() macro that calculates the offset
of a certain field in the struct RISCVCPUConfig. We're going to use this
macro in target/riscv/cpu.c as well in the next patches. Make it public.

Rename it to CPU_CFG_OFFSET() for more clarity while we're at it.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230912132423.268494-15-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>