Char: ds1286, eliminate busy waiting

ds1286_get_time(); is not called from atomic context, sleep for 20 ms is
better choice than a (home-made) busy waiting for such a situation.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/ds1286.c

@@ -443,7 +443,6 @@ static void ds1286_get_time(struct rtc_time *rtc_tm)
 {
 	unsigned char save_control;
 	unsigned long flags;
-	unsigned long uip_watchdog = jiffies;
 
 	/*
 	 * read RTC once any update in progress is done. The update
@@ -456,8 +455,7 @@ static void ds1286_get_time(struct rtc_time *rtc_tm)
 	 */
 
 	if (ds1286_is_updating() != 0)
-		while (time_before(jiffies, uip_watchdog + 2*HZ/100))
-			barrier();
+		msleep(20);
 
 	/*
 	 * Only the values that we read from the RTC are set. We leave