iwlwifi: move ucode notification from iwl_priv to iwl_shared

Move the notification structures for ucode operations from the
iwl_priv structure to the iwl_shared structure, with associated
code changes.

Signed-off-by: Don Fry <donald.h.fry@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>