iwlwifi: Revert "iwlwifi: pcie: dynamic Tx command queue size"

This reverts commit dd05f9aa.

Shorter TX queues support was added eventually without the
need for the parameters this patch added.

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