[V2] rdmsr before the CPUID test produces KVM warning

If KVM does not support INTEL_PT, guest MSR_IA32_RTIT_CTL reading will produce host warning like "kvm [2469]: vcpu0 unhandled rdmsr: 0x570". Guest can determine whether the CPU supports Intel_PT according to CPUID, so test_cpu_cap function is added before rdmsr,and it is more in line with the

[V2] rdmsr before the CPUID test produces KVM warning

If KVM does not support INTEL_PT, guest MSR_IA32_RTIT_CTL reading will produce host warning like kvm [2469]: vcpu0 unhandled rdmsr: 0x570. Guest can determine whether the CPU supports Intel_PT according to CPUID, so test_cpu_cap function is added before rdmsr,and it is more in line with the code