perf tools: Add missing util.h to pick up 'page_size' variable

Not to depend of getting it indirectly.

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-tirjsmvu4ektw0k7lm8k9lhu@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/machine.c

@@ -15,6 +15,7 @@
 #include "strlist.h"
 #include "thread.h"
 #include "vdso.h"
+#include "util.h"
 #include <stdbool.h>
 #include <sys/types.h>
 #include <sys/stat.h>