orinoco: initialise priv->hw before assigning the interrupt

The interrupt handler takes a lock - but since commit bcad6e80 this
lock goes through an indirection specified in the hermes_t structure.
We must therefore initialise the structure before setting up the
interrupt handler.

Fix orinoco_cs and spectrum_cs

<https://bugzilla.kernel.org/show_bug.cgi?id=23932

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Bisected by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off by: David Kilroy <kilroyd@googlemail.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>