iwlwifi: remove 4965 from common uCode API structures

This patch removes 4965 from common uCode API structures. Also updates
iwlagn commands with 3945 specific RX command in preparation for 3945 port.

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