orinoco: Resume spectrum_cs in the same way as orinoco_cs

Retrieval of external firmware has been resolved, and should work with
the standard orinoco resume algorithm.

This fixes an issue where priv->hw_unavailable indicates the card is
ready when firmware has not been loaded.

Signed-off by: David Kilroy <kilroyd@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>