iwlwifi: refactor TX response flow

This patch utilize 5000 new TX response command
which contains all necessary information and avoids
back referencing to the original TX frame.
It also change handling of software queue tracking
4965 flow is aligned with changes as much as possible.

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