KVM: TDX: Make TDX VM type supported

Now all the necessary code for TDX is in place, it's ready to run TDX
guest.  Advertise the VM type of KVM_X86_TDX_VM so that the user space
VMM like QEMU can start to use it.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
---
TDX "the rest" v2:
- No change.

TDX "the rest" v1:
- Move down to the end of patch series.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/main.c

@@ -1091,6 +1091,7 @@ static int __init vt_init(void)
 				sizeof(struct vcpu_tdx));
 		vcpu_align = max_t(unsigned, vcpu_align,
 				__alignof__(struct vcpu_tdx));
+		kvm_caps.supported_vm_types |= BIT(KVM_X86_TDX_VM);
 	}
 
 	/*