Staging: w35und: clean up adapter.h a bit

This patch cleans up adapter.h a bit in preparation for merging struct
wb35_adapter to struct wbsoft_priv.

Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>