ARC: perf: introduce Kernel PMU events support

Export all available ARC architected hardware events as
kernel PMU events to make non-generic events accessible.

ARC PMU HW allow us to read the list of all available
events names. So we generate kernel PMU event list
dynamically in arc_pmu_device_probe() using
human-readable events names we got from HW instead of
using pre-defined events list.

-------------------------->8--------------------------
$ perf list
  [snip]
  arc_pmu/bdata64/                  [Kernel PMU event]
  arc_pmu/bdcstall/                 [Kernel PMU event]
  arc_pmu/bdslot/                   [Kernel PMU event]
  arc_pmu/bfbmp/                    [Kernel PMU event]
  arc_pmu/bfirqex/                  [Kernel PMU event]
  arc_pmu/bflgstal/                 [Kernel PMU event]
  arc_pmu/bflush/                   [Kernel PMU event]
-------------------------->8--------------------------

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>