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

To pick up the changes in:

  a85cbe61 ("uapi: move constants from <linux/kernel.h> to <linux/const.h>")

That causes no changes in tooling, just addresses this perf build
warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/const.h' differs from latest version at 'include/uapi/linux/const.h'
  diff -u tools/include/uapi/linux/const.h include/uapi/linux/const.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: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>