bigos: add an early prototype for IBS

Add some stuff to prepare IBS handling.
Most of the work is already done by xenoprof. Only the NMI needs to be
implemented again.
Still need to hide it behind a clean IBS interface.
bigos: add a clean interface for IBS

Hide all the Xenoprofile stuff behind a clean IBS interface.
This should be enought for now, refactoring may be needed later...
Also add a dummy pebs_capable() which always return 0 but should be
implemented for the Intel cpus work.
Merge branch 'ibs' into develop
bigos: add an implementation of pebs_capable()

Add a real implementation for pebs_capable checking if cpu model is
Intel and if is has the DS capability.
bigos: change the PEBS interface

Modify the PEBS interface so it looks like the IBS one.
There is no need to have separated work on the different cpus, neither
to have several PEBS working (even if technically possible) at the
same time on the same core.
Merge branch 'pebs' into develop