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/python.c

@@ -12,6 +12,7 @@
 #include "print_binary.h"
 #include "thread_map.h"
 #include "mmap.h"
+#include "util.h"
 
 #if PY_MAJOR_VERSION < 3
 #define _PyUnicode_FromString(arg) \