tools headers UAPI: Sync linux/perf_event.h with the kernel sources

To pick up the changes in:

  09519ec3 ("perf: Add perf_event_attr::config3")

The patches for the tooling side will come later.

This addresses this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/perf_event.h' differs from latest version at 'include/uapi/linux/perf_event.h'
  diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/lkml/ZAZLYmDjWjSItWOq@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>