atl1c: wrong register used to stop TXQ

function atl1c_stop_mac uses wrong register of REG_TWSI_CTRL
to stop mac, replace it with REG_TXQ_CTRL.

Signed-off-by: xiong <xiong@qca.qualcomm.com>
Tested-by: Liu David <dwliu@qca.qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>