[POWERPC] via-pmu: remove LED sleep notifier

The generic LED code now makes sure that suspended devices don't blink,
so we no longer need to do it ourselves. For the suspend to disk case,
however, we need to make sure that we don't blink if the PMU sysdev
was suspended before the LED device.

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