orinoco: Do not call wiphy_unregister() from free_orinocodev()

alloc_orinocodev() would allocate the wiphy entry, but it would only get
registered much later in orinoco_init(). If something failed in the init
process inbetween the call to alloc_orinocodev() and the completion
of orinoco_init(), the drivers would end up calling wiphy_unregister()
with a NULL pointer causing beautiful OOPS fireworks.

Explicitly call wiphy_unregister() instead in the right places.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>