Host AP driver used hardware model specific dev_open/close handlers
that were called on dev_open/close if the hardware driver had
registered the handler. These were only used for hostap_cs and only
for tracking whether any of the netdevs were UP. This information is
already available from local->num_dev_open, so there is not need for
the special open/close handler.

Let's get rid of these handlers. In addition to cleaning up the code,
this fixes a module refcounting issue for hostap_cs where ejecting the
card while any of the netdevs were open did not decrement refcount
properly.
Signed-off-by: Jouni Malinen <jkmaline@cc.hut.fi>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>