ath11k: fix WARN_ON during ath11k_mac_update_vif_chan

Fix WARN_ON() from ath11k_mac_update_vif_chan() if vdev is not up.
Since change_chanctx can be called even before vdev_up from
ieee80211_start_ap->ieee80211_vif_use_channel->
ieee80211_recalc_radar_chanctx.

Do vdev stop followed by a vdev start in case of vdev is down.

Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.5.0.1-01100-QCAHKSWPL_SILICONZ-1

Signed-off-by: Venkateswara Naralasetty <quic_vnaralas@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/1644416019-820-1-git-send-email-quic_vnaralas@quicinc.com