ath11k: Avoid reg rules update during firmware recovery

During firmware recovery, the default reg rules which are
received via WMI_REG_CHAN_LIST_CC_EVENT can overwrite
the currently configured user regd.

See below snap for example,

root@OpenWrt:/# iw reg get | grep country
country FR: DFS-ETSI
country FR: DFS-ETSI
country FR: DFS-ETSI
country FR: DFS-ETSI

root@OpenWrt:/# echo assert > /sys/kernel/debug/ath11k/ipq8074\ hw2.0/simulate_f
w_crash
<snip>
[ 5290.471696] ath11k c000000.wifi1: pdev 1 successfully recovered

root@OpenWrt:/# iw reg get | grep country
country FR: DFS-ETSI
country US: DFS-FCC
country US: DFS-FCC
country US: DFS-FCC

In the above, the user configured country 'FR' is overwritten
when the rules of default country 'US' are received and updated during
recovery. Hence avoid processing of these rules in general
during firmware recovery as they have been already applied during
driver registration or after last set user country is configured.

This scenario applies for both AP and STA devices basically because
cfg80211 is not aware of the recovery and only the driver recovers, but
changing or resetting of the reg domain during recovery is not needed so
as to continue with the configured regdomain currently in use.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.4.0.1-01460-QCAHKSWPL_SILICONZ-1
Signed-off-by: Sriram R <srirrama@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210721212029.142388-3-jouni@codeaurora.org

drivers/net/wireless/ath/ath11k/wmi.c

@@ -5848,6 +5848,17 @@ static int ath11k_reg_chan_list_event(struct ath11k_base *ab, struct sk_buff *sk
 
 	pdev_idx = reg_info->phy_id;
 
+	/* Avoid default reg rule updates sent during FW recovery if
+	 * it is already available
+	 */
+	spin_lock(&ab->base_lock);
+	if (test_bit(ATH11K_FLAG_RECOVERY, &ab->dev_flags) &&
+	    ab->default_regd[pdev_idx]) {
+		spin_unlock(&ab->base_lock);
+		goto mem_free;
+	}
+	spin_unlock(&ab->base_lock);
+
 	if (pdev_idx >= ab->num_radios) {
 		/* Process the event for phy0 only if single_pdev_only
 		 * is true. If pdev_idx is valid but not 0, discard the