KVM: VMX: Configure runtime hooks using vmx_x86_ops

Configure VMX's runtime hooks by modifying vmx_x86_ops directly instead
of using the global kvm_x86_ops.  This sets the stage for waiting until
after ->hardware_setup() to set kvm_x86_ops with the vendor's
implementation.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200321202603.19355-5-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>