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

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

Move 'clust_name' inside the loop, and g_autofree, to avoid having to
g_free() manually in each loop iteration.

'intc_phandles' is also g_autofreed to avoid another manual g_free().

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240122221529.86562-5-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>