kprobes: unused header files removed

As kernel test robot reported, lib/test_objpool.c (trace:probes/for-next)
has linux/version.h included, but version.h is not used at all. Then more
unused headers are found in test_objpool.c and rethook.c, and all of them
should be removed.

Link: https://lore.kernel.org/all/20231023112245.6112-1-wuqiang.matt@bytedance.com/Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310191512.vvypKU5Z-lkp@intel.com/Signed-off-by: wuqiang.matt <wuqiang.matt@bytedance.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

kernel/trace/rethook.c

@@ -8,8 +8,6 @@
 #include <linux/preempt.h>
 #include <linux/rethook.h>
 #include <linux/slab.h>
-#include <linux/sort.h>
-#include <linux/smp.h>
 
 /* Return hook list (shadow stack by list) */
 

lib/test_objpool.c

@@ -6,21 +6,15 @@
  * Copyright: wuqiang.matt@bytedance.com
  */
 
-#include <linux/version.h>
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/sched.h>
-#include <linux/cpumask.h>
 #include <linux/completion.h>
 #include <linux/kthread.h>
-#include <linux/cpu.h>
-#include <linux/cpuset.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
 #include <linux/hrtimer.h>
-#include <linux/interrupt.h>
 #include <linux/objpool.h>
 
 #define OT_NR_MAX_BULK (16)