timekeeping: Use ktime_t based data for ktime_get()

Speed up ktime_get() by using ktime_t based data. Text size shrinks by
64 bytes on x8664.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

kernel/time/timekeeping.c

@@ -407,18 +407,19 @@ ktime_t ktime_get(void)
 {
 	struct timekeeper *tk = &tk_core.timekeeper;
 	unsigned int seq;
-	s64 secs, nsecs;
+	ktime_t base;
+	s64 nsecs;
 
 	WARN_ON(timekeeping_suspended);
 
 	do {
 		seq = read_seqcount_begin(&tk_core.seq);
-		secs = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
-		nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
+		base = tk->base_mono;
+		nsecs = timekeeping_get_ns(tk);
 
 	} while (read_seqcount_retry(&tk_core.seq, seq));
 
-	return ktime_set(secs, nsecs);
+	return ktime_add_ns(base, nsecs);
 }
 EXPORT_SYMBOL_GPL(ktime_get);