iwlwifi: make led functions generic

Led functions are generic for all the devices except 3945, so remove the
reference to 4965

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>