ntp: Introduce and use SECS_PER_DAY macro instead of 86400

Currently the leapsecond logic uses what looks like magic values.

Improve this by defining SECS_PER_DAY and using that macro
to make the logic more clear.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1434063297-28657-3-git-send-email-john.stultz@linaro.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/ntp.c

@@ -35,6 +35,7 @@ unsigned long			tick_nsec;
 static u64			tick_length;
 static u64			tick_length_base;
 
+#define SECS_PER_DAY		86400
 #define MAX_TICKADJ		500LL		/* usecs */
 #define MAX_TICKADJ_SCALED \
 	(((MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
@@ -390,7 +391,7 @@ int second_overflow(unsigned long secs)
 	case TIME_INS:
 		if (!(time_status & STA_INS))
 			time_state = TIME_OK;
-		else if (secs % 86400 == 0) {
+		else if (secs % SECS_PER_DAY == 0) {
 			leap = -1;
 			time_state = TIME_OOP;
 			printk(KERN_NOTICE
@@ -400,7 +401,7 @@ int second_overflow(unsigned long secs)
 	case TIME_DEL:
 		if (!(time_status & STA_DEL))
 			time_state = TIME_OK;
-		else if ((secs + 1) % 86400 == 0) {
+		else if ((secs + 1) % SECS_PER_DAY == 0) {
 			leap = 1;
 			time_state = TIME_WAIT;
 			printk(KERN_NOTICE