drivers: macintosh: rack-meter: limit idle ticks to total ticks

Limit idle ticks to total ticks. This prevents the annoying rackmeter
leds fully ON / OFF blinking state that happens on fully idling
G5 Xserve systems.
Signed-off-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

drivers/macintosh/rack-meter.c

@@ -227,6 +227,7 @@ static void rackmeter_do_timer(struct work_struct *work)
 
 	total_idle_ticks = get_cpu_idle_time(cpu);
 	idle_ticks = (unsigned int) (total_idle_ticks - rcpu->prev_idle);
+	idle_ticks = min(idle_ticks, total_ticks);
 	rcpu->prev_idle = total_idle_ticks;
 
 	/* We do a very dumb calculation to update the LEDs for now,