KVM: x86: move vm_destroy callback at end of kvm_arch_destroy_vm

KVM: x86: move vm_destroy callback at end of kvm_arch_destroy_vm

TDX needs to free the TDR control structures last, after all paging structures
have been torn down; move the vm_destroy callback at a suitable place.
The new place is also okay for AMD; the main difference is that the
MMU has been torn down and, if anything, that is better done before
the SNP ASID is released.

Extracted from a patch by Yan Zhao.

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