perf tools: Remove poll.h and wait.h from util.h

Not needed in this header, added to the places that need poll(), wait()
and a few other prototypes.

Link: http://lkml.kernel.org/n/tip-i39c7b6xmo1vwd9wxp6fmkl0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/event-times.c

@@ -2,6 +2,7 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <string.h>
+#include <sys/wait.h>
 #include "tests.h"
 #include "evlist.h"
 #include "evsel.h"