iwlwifi: rename iwl-4965-io.h to iwl-io.h

This patch renames iwl-4965-io.h back to iw-io.h
it also remove 4965 from all functions it supplies

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>