tools x86 machine: Add missing util.h to pick up 'page_size'

We're getting it by sheer luck, add that util.h to get the 'page_size'
definition.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-347078mgj3d2jfygtxs4ntti@git.kernel.org


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