iwlwifi: tid_data logic move to upper layer - check_empty

The tid_data is not related to the transport layer, so move
the logic that depends on it to the upper layer.
This patch deals with the code that checks if there are still
pending packets for an RA / TID.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>