x86/perf/intel/cstate: Sanitize probing

The whole probing functionality can simply be expressed with model matching
and a bunch of structures describing the variants. This is a first step to
make that driver modular.

While at it, get rid of completely pointless comments and name the enums so
they are self explaining.

Signed-off-by: Thomas Gleixner <[email protected]>
[ Reworked probing to clear msr[].attr for all !present msrs. ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Vince Weaver <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

Author: KAGA-KOKO