cyclictest: remove inclusion of unnecessary headers

The following three headers seem to be unnecessary,
and do not exist on FreeBSD.

Remove them.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: John Kacur <jkacur@redhat.com>

src/cyclictest/cyclictest.c

@@ -22,11 +22,8 @@
 #include <time.h>
 #include <errno.h>
 #include <limits.h>
-#include <linux/unistd.h>
 
-#include <sys/prctl.h>
 #include <sys/stat.h>
-#include <sys/sysinfo.h>
 #include <sys/types.h>
 #include <sys/time.h>
 #include <sys/resource.h>