pda_power: Add support for using otg transceiver events

If the platform data sets the use_otg_notifier flag,
the driver will now register an otg notifier callback and listen
to transceiver events for AC/USB plug-in events instead. This would
normally be used by not specifying is_xx_online callbacks and
not specifying any irqs so the state machine is completely driven
from OTG xceiver events.

Signed-off-by: Dima Zavin <dima@android.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>