KVM: x86: return 1 unconditionally for availability of KVM_CAP_VAPIC

The two ioctls used to implement userspace-accelerated TPR,
KVM_TPR_ACCESS_REPORTING and KVM_SET_VAPIC_ADDR, are available
even if hardware-accelerated TPR can be used.  So there is
no reason not to report KVM_CAP_VAPIC.

Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>