iwlwifi: fix 4965 notification wait setup

The notification wait support code is shared
between 4965 and other AGN devices, so 4965
also has to initialize the data structures
for it, otherwise it crashes.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>