target/loongarch: Implement kvm_arch_init function

Implement the kvm_arch_init of loongarch, in the function, the
KVM_CAP_MP_STATE cap is checked by kvm ioctl.

Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
Signed-off-by: xianglai li <lixianglai@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20240105075804.1228596-6-zhaotianrui@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>

target/loongarch/kvm/kvm.c

@@ -665,6 +665,7 @@ int kvm_arch_get_default_type(MachineState *ms)
 
 int kvm_arch_init(MachineState *ms, KVMState *s)
 {
+    cap_has_mp_state = kvm_check_extension(s, KVM_CAP_MP_STATE);
     return 0;
 }