Split the PMU events into meaningful functional groups.  Update core pmu
events based on supported ARMv8 recommended IMPLEMENTATION DEFINED
events.

The JSON files are updated with reference to a PMU table shared here:

  https://github.com/AmpereComputing/ampere-centos-kernel/blob/amp-centos-7.5-kernel/Documentation/arm64/eMAG-ARM-CoreImpDefined.pdf

Changes in v3:
- Removed CHAIN event as it wouldn't be useful in Perf - William
- Will factor out events 0x00-0x38 in a follow-on patch - William
- to armv8-recommended.json
Changes in V2:
- Provided documentation for changes - John, William
- Broke up into meaningful groups - William
Signed-off-by: Sean V Kelley <seanvk.dev@oregontracks.org>
Reviewed-by: William Cohen <wcohen@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org
LPU-Reference: 20180916221203.7935-1-seanvk.dev@oregontracks.org
Link: https://lkml.kernel.org/n/tip-tzvs1ip6srcv2et0ny58e0wy@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>