hw/riscv: virt: Simplify virt_{get,set}_aclint()

hw/riscv: virt: Simplify virt_{get,set}_aclint()

There is no need to declare an intermediate "MachineState *ms".

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230206085007.3618715-1-bmeng@tinylab.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>