tools headers UAPI: Copy seccomp.h to be able to build 'perf bench' in older systems

The new 'perf bench' for sched-seccomp-notify uses defines and types not
available in older systems where we want to have perf available, so grab
a copy of this UAPI from the kernel sources to allow that.

This will be checked in the future for drift from the original when we
build the perf tool, that will warn when that happens like:

  make: Entering directory '/var/home/acme/git/perf-tools/tools/perf'
    BUILD:   Doing 'make -j32' parallel build
  Warning: Kernel ABI header differences:

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/ZQGhMXtwX7RvV3ya@kernel.org


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