Second part of the kldload patches for cardbus. This makes
kldload of a driver for a device that's inserted now appears
to work. To make it work, we only do a power cycle of the card
if there's no children drivers attached.
This likely is papering over bogosities in the power system. The
power sequence needs to be re-written, so I'll not worry about
the papering over until the re-write.