iwlwifi: mvm: Remove unused inline function iwl_mvm_tid_to_ac_queue

commit cfbc6c4c ("iwlwifi: mvm: support mac80211 TXQs model")
left behind this, remove it.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20200506134217.49760-1-yuehaibing@huawei.com


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>