timekeeping: Use timekeeping_update() instead of memcpy()

We already have a function which does the right thing, that also makes
sure that the coming ktime_t based cached values are getting updated.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

kernel/time/timekeeping.c

@@ -883,8 +883,7 @@ void __init timekeeping_init(void)
 	tmp.tv_nsec = 0;
 	tk_set_sleep_time(tk, tmp);
 
-	memcpy(&shadow_timekeeper, &tk_core.timekeeper,
-	       sizeof(tk_core.timekeeper));
+	timekeeping_update(tk, TK_MIRROR);
 
 	write_seqcount_end(&tk_core.seq);
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);