perf tests cpumap: Add missing headers

It was getting all sort of needed stuff by sheer luck, via indirect
includes, fix it.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/cpumap.c

···
 #include "tests.h"
+#include <stdio.h>
 #include "cpumap.h"
+#include "event.h"
+#include <string.h>
+#include <linux/bitops.h>
+#include "debug.h"
+
+struct machine;
 
 static int process_event_mask(struct perf_tool *tool __maybe_unused,
 			 union perf_event *event,