wifi: ath11k: stop tx queues immediately upon firmware exit

Currently, recovery flag is set immediately upon firmware
exit but tx queues are stopped once firmware arrives back
and is ready which is during ath11k_core_restart. Once
ieee80211 hw restart is completed, tx queues are resumed.
If during the time delta between firmware exit and firmware
ready, mac80211 send packets, currently ath11k will drop it
since recovery flag will be set. But warning prints will
come -
  "ath11k c000000.wifi: failed to transmit frame -108"

If more tx packets are there, this could lead to flooding
of above print.

However, actually tx queues should be stopped immediately
when firmware leaves. This will prevent packets to get
dropped when firmware is recovering.

Add fix to stop tx queues immediately after firmware exit.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-01100-QCAHKSWPL_SILICONZ-1

Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220923170235.18873-1-quic_adisi@quicinc.com