cpu: Add Haswell-noTSX-IBRS CPU model
    
    This is a variant of Haswell-noTSX with indirect branch prediction
    protection. The only difference between Haswell-noTSX and
    Haswell-noTSX-IBRS is the added "spec-ctrl" feature.
    
    The Haswell-noTSX-IBRS model in QEMU is a bit different since
    Haswell-noTSX got several additional features since we added it in
    cpu_map.xml:
        arat, abm, f16c, rdrand, vme, xsaveopt
    
    Adding them only to the -IBRS variant would confuse our CPU detection
    code.
    
    Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
    Reviewed-by: Pavel Hrdina <phrdina@redhat.com>