hw/riscv/virt.c: use g_autofree in create_fdt_virtio()

hw/riscv/virt.c: use g_autofree in create_fdt_virtio()

Put 'name' declaration inside the loop, with g_autofree, to avoid
manually doing g_free() in each iteration.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240122221529.86562-6-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>