avr32: Convert avr32 to use read/update_persistent_clock

This patch converts the avr32 architecture to use the generic
read_persistent_clock and update_persistent_clock interfaces, reducing
the amount of arch specific code we have to maintain, and allowing for
further cleanups in the future.

I have not built or tested this patch, so help from arch maintainers
would be appreciated.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1267675049-12337-7-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/avr32/kernel/time.c

@@ -110,17 +110,17 @@ static struct clock_event_device comparator = {
 	.set_mode	= comparator_mode,
 };
 
+void read_persistent_clock(struct timespec *ts)
+{
+	ts->tv.sec = mktime(2007, 1, 1, 0, 0, 0);
+	ts->tv_nsec = 0;
+}
+
 void __init time_init(void)
 {
 	unsigned long counter_hz;
 	int ret;
 
-	xtime.tv_sec = mktime(2007, 1, 1, 0, 0, 0);
-	xtime.tv_nsec = 0;
-
-	set_normalized_timespec(&wall_to_monotonic,
-				-xtime.tv_sec, -xtime.tv_nsec);
-
 	/* figure rate for counter */
 	counter_hz = clk_get_rate(boot_cpu_data.clk);
 	counter.mult = clocksource_hz2mult(counter_hz, counter.shift);