[POWERPC] Generic time suspend/resume code

This removes the time suspend/restore code that was done through
a PMU notifier in arch/platforms/powermac/time.c.

Instead, introduce arch/powerpc/sysdev/timer.c which creates a sys
device and handles time of day suspend/resume through that.

This should probably be replaced by using the generic RTC framework
but for now it gets rid of the arcane powermac specific hack.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/powermac/time.c

@@ -297,49 +297,11 @@ int __init via_calibrate_decr(void)
 }
 #endif
 
-#ifdef CONFIG_PM
-/*
- * Reset the time after a sleep.
- */
-static int
-time_sleep_notify(struct pmu_sleep_notifier *self, int when)
-{
-	static unsigned long time_diff;
-	unsigned long flags;
-	unsigned long seq;
-	struct timespec tv;
-
-	switch (when) {
-	case PBOOK_SLEEP_NOW:
-		do {
-			seq = read_seqbegin_irqsave(&xtime_lock, flags);
-			time_diff = xtime.tv_sec - pmac_get_boot_time();
-		} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-		break;
-	case PBOOK_WAKE:
-		tv.tv_sec = pmac_get_boot_time() + time_diff;
-		tv.tv_nsec = 0;
-		do_settimeofday(&tv);
-		break;
-	}
-	return PBOOK_SLEEP_OK;
-}
-
-static struct pmu_sleep_notifier time_sleep_notifier = {
-	time_sleep_notify, SLEEP_LEVEL_MISC,
-};
-#endif /* CONFIG_PM */
-
 /*
  * Query the OF and get the decr frequency.
  */
 void __init pmac_calibrate_decr(void)
 {
-#if defined(CONFIG_PM) && defined(CONFIG_ADB_PMU)
-	/* XXX why here? */
-	pmu_register_sleep_notifier(&time_sleep_notifier);
-#endif
-
 	generic_calibrate_decr();
 
 #ifdef CONFIG_PPC32