KVM: nSVM: move nested vmrun tracepoint to enter_svm_guest_mode

This way trace will capture all the nested mode entries
(including entries after migration, and from smm)

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210217145718.1217358-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>