Revert "kernel: remove unused CONFIG guard becuase GKI kernel enable kprobe by default" (#2495)

follow up to
https://github.com/tiann/KernelSU/pull/2475#issuecomment-2680947145

kernel/core_hook.c

@@ -886,7 +886,9 @@ void __init ksu_core_init(void)
 
 void ksu_core_exit(void)
 {
+#ifdef CONFIG_KPROBES
 	pr_info("ksu_core_kprobe_exit\n");
 	// we dont use this now
 	// ksu_kprobe_exit();
+#endif
 }