LoongArch: Fix early_numa_add_cpu() usage for FDT systems

early_numa_add_cpu() applies on physical CPU id rather than logical CPU
id, so use cpuid instead of cpu.

Cc: stable@vger.kernel.org
Fixes: 3de9c42d ("LoongArch: Add all CPUs enabled by fdt to NUMA node 0")
Reported-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>