local->hw_priv was initialized only after the interrupt handler was
registered. This could trigger a NULL pointer dereference in
prism2_pccard_card_present() that assumed that local->hw_priv is always
set (and it should have been). Fix this by setting local->hw_priv before
registering the interrupt handler.

Signed-off-by: Jouni Malinen <jkmaline@cc.hut.fi>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>