ntp: handle leap second via timer

Remove the leap second handling from second_overflow(), which doesn't have to
check for it every second anymore.  With CONFIG_NO_HZ this also makes sure the
leap second is handled close to the full second.  Additionally this makes it
possible to abort a leap second properly by resetting the STA_INS/STA_DEL
status bits.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 3509447..55e434f 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -93,6 +93,8 @@
 #endif
 };
 
+extern struct clocksource *clock;	/* current clocksource */
+
 /*
  * Clock source flags bits::
  */
diff --git a/include/linux/timex.h b/include/linux/timex.h
index da431f8..fc6035d 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -212,6 +212,7 @@
 
 extern long time_adjust;	/* The amount of adjtime left */
 
+extern void ntp_init(void);
 extern void ntp_clear(void);
 
 /**