perf/x86: Export Sandy Bridge uncore clockticks event in sysfs

perf/x86: Export Sandy Bridge uncore clockticks event in sysfs

This patch exports the clockticks event and its encoding to user level.
The clockticks event was exported for Nehalem/Westmere but not for Sandy
Bridge (client). Given that it uses a special encoding, it needs to be
exported to user tools, so users can do:

  # perf stat -a -C 0 -e uncore_cbox_0/clockticks/ sleep 1

Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120829130122.GA32336@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>