posix-timers: Make nanosleep timespec argument const

No nanosleep implementation modifies the rqtp argument. Mark is const.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index d83b7ed..255edd5 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -454,7 +454,7 @@
 /* Precise sleep: */
 
 extern int nanosleep_copyout(struct restart_block *, struct timespec *);
-extern long hrtimer_nanosleep(struct timespec64 *rqtp,
+extern long hrtimer_nanosleep(const struct timespec64 *rqtp,
 			      const enum hrtimer_mode mode,
 			      const clockid_t clockid);