TFD_*_SLOTS and IWL_*_QUEUE_SIZE both define the TX queue
size (number of TFDs).
Get rid of TFD_*_SLOTS and use only IWL_*_QUEUE_SIZE.
Signed-off-by: NShaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>