iwlwifi: pcie: introduce new tfd and tb formats

New hardware supports bigger TFDs and TBs.
Introduce the new formats and adjust defines and code
relying on old format.
Changing the actual TFD allocation is trickier and
deferred to the next patch.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>