iwl3945: Getting rid of iwl-3945-led.h

The duplicated LED definitions prevent one from including iwl-dev.h from the
3945 specific C files.
Moreover, we are sharing many definitions between iwl-3945-led.h and
iwl-led.h, so let's just use the iwl one. Note that this file will get more
cleanups once we share a common iwl_priv structure.

Signed-off-by: Samuel Ortiz <samuel.ortiz@intel.com>
Acked-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>