Revert "iwlagn: sysfs couldn't find the priv pointer"

This reverts commit cc1a93e6.

This fix introduced a bug: bad pointer in unload.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>