kernel: Add header guard and support Official KernelSU fd wrapper

* Based on unmerged pull-request
https://github.com/tiann/KernelSU/pull/ 2285

Co-authored-by: Ylarod <me@ylarod.cn>
Signed-off-by: Faris <rissu.ntk@gmail.com>

kernel/file_wrapper.h

@@ -1,3 +1,6 @@
+#ifndef __KSU_H_FILE_WRAPPER
+#define __KSU_H_FILE_WRAPPER
+
 #include <linux/file.h>
 #include <linux/fs.h>
 
@@ -8,3 +11,5 @@ struct ksu_file_wrapper {
 
 struct ksu_file_wrapper *mksu_create_file_wrapper(struct file *fp);
 void mksu_delete_file_wrapper(struct ksu_file_wrapper *data);
+
+#endif