ABM is only implemented as a single instruction set by AMD; all AMD
processors support both instructions or neither. Intel considers POPCNT
as part of SSE4.2, and LZCNT as part of BMI1, but Intel also uses AMD's
ABM flag to indicate support for both POPCNT and LZCNT.  It has to be
added to Haswell and Broadwell because Haswell, by adding LZCNT, has
completed the ABM.

Tested with "qemu-kvm -cpu Haswell-noTSX,enforce" (and also with older
machine types) on an Haswell-EP machine.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>