KVM: x86: nSVM: restore the L1 host state prior to resuming nested guest on SMM exit

Otherwise guest entry code might see incorrect L1 state (e.g paging state).

Fixes: 37be407b

 ("KVM: nSVM: Fix L1 state corruption upon return from SMM")

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210913140954.165665-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>