ath10k-ct: Support AQL on ath10k CT_KVER-5.4

Commit ea50780 backported Airtime Queue Limits (AQL) from Linux 5.5
to OpenWrt's backports 5.4. However, this only enabled AQL for the
vanilla ath10k driver. This patch also enables it for ath10k-ct.

Tested on:
* 2xTP-Link Archer A7v5 (QCA9563/QCA988X)
* Backports version 5.4-rc8 & 5.4.27
* ath10k-ct and ath10k-ct-htt firmware version 014 to 017
* ath10k-ct driver versions dc025dc to 3d173a4 (CT_KVER-5.4)
* WPA2, 802.11krv

Tested since January 25, 2020.

Signed-off-by: Jose Olivera <oliverajeo@gmail.com>

package/kernel/ath10k-ct/patches/205-ath10k-Add-NL80211_EXT_FEATURE_AQL-flag.patch

@@ -0,0 +1,10 @@
+--- a/ath10k-5.4/mac.c
++++ b/ath10k-5.4/mac.c
+@@ -10180,6 +10180,7 @@ int ath10k_mac_register(struct ath10k *a
+ 	wiphy_ext_feature_set(ar->hw->wiphy, NL80211_EXT_FEATURE_VHT_IBSS);
+ 	wiphy_ext_feature_set(ar->hw->wiphy,
+ 			      NL80211_EXT_FEATURE_SET_SCAN_DWELL);
++	wiphy_ext_feature_set(ar->hw->wiphy, NL80211_EXT_FEATURE_AQL);
+ 
+ 	if (test_bit(WMI_SERVICE_TX_DATA_ACK_RSSI, ar->wmi.svc_map) ||
+ 	    test_bit(WMI_SERVICE_HTT_MGMT_TX_COMP_VALID_FLAGS, ar->wmi.svc_map))