kselftests: cgroup: remove duplicated include from test_freezer.c

Remove duplicated include.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/cgroup/test_freezer.c

@@ -11,7 +11,6 @@
 #include <stdlib.h>
 #include <sys/inotify.h>
 #include <string.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 
 #include "../kselftest.h"