ARC: remove extraneous __KERNEL__ guards

Verified by doing make headers_install as none of these files are
exported to userspace

arch/arc/include/asm/thread_info.h

@@ -16,8 +16,6 @@
 #ifndef _ASM_THREAD_INFO_H
 #define _ASM_THREAD_INFO_H
 
-#ifdef __KERNEL__
-
 #include <asm/page.h>
 
 #ifdef CONFIG_16KSTACKS
@@ -114,6 +112,4 @@ static inline __attribute_const__ struct thread_info *current_thread_info(void)
  * syscall, so all that reamins to be tested is _TIF_WORK_MASK
  */
 
-#endif /* __KERNEL__ */
-
 #endif /* _ASM_THREAD_INFO_H */