KVM: x86: Uncondtionally skip MMU sync/TLB flush in MOV CR3's PGD switch

Stop leveraging the MMU sync and TLB flush requested by the fast PGD
switch helper now that kvm_set_cr3() manually handles the necessary sync,
frees, and TLB flush.  This will allow dropping the params from the fast
PGD helpers since nested SVM is now the odd blob out.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>