KVM: SVM: Inject #GP on guest MSR_TSC_AUX accesses if RDTSCP unsupported

Inject #GP on guest accesses to MSR_TSC_AUX if RDTSCP is unsupported in
the guest's CPUID model.

Fixes: 46896c73 ("KVM: svm: add support for RDTSCP")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210423223404.3860547-2-seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>