ath10k-ct: limit available channels via DT

This backports upstream commit

34d5629 ath10k: limit available channels via DT ieee80211-freq-limit

to the 4.19 ath10k-ct version. Without this patch, disabled channels
are still listed as a supported configuration for the radio.

The identical patch was also backported by OpenWRT to the non-ct driver.
It can be dropped as soon as we switch to an ath10k-ct version based on
4.20 or higher.

Signed-off-by: David Bauer <mail@david-bauer.net>

package/kernel/ath10k-ct/patches/203-ath10k-Limit-available-channels-via-DT-ieee80211-fre.patch

@@ -0,0 +1,39 @@
+From bbf0a8af2261bc7ae39b227ff6a1e9f45a008c27 Mon Sep 17 00:00:00 2001
+From: Sven Eckelmann <sven.eckelmann@openmesh.com>
+Date: Mon, 30 Jul 2018 17:31:41 +0200
+Subject: [PATCH] ath10k: Limit available channels via DT ieee80211-freq-limit
+
+Tri-band devices (1x 2.4GHz + 2x 5GHz) often incorporate special filters in
+the RX and TX path. These filtered channel can in theory still be used by
+the hardware but the signal strength is reduced so much that it makes no
+sense.
+
+There is already a DT property to limit the available channels but ath10k
+has to manually call this functionality to limit the currrently set wiphy
+channels further.
+
+Signed-off-by: Sven Eckelmann <sven.eckelmann@openmesh.com>
+
+Forwarded: https://patchwork.kernel.org/patch/10549245/
+---
+ drivers/net/wireless/ath/ath10k/mac.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/ath10k-4.19/mac.c
++++ b/ath10k-4.19/mac.c
+@@ -18,6 +18,7 @@
+ 
+ #include "mac.h"
+ 
++#include <net/cfg80211.h>
+ #include <net/mac80211.h>
+ #include <linux/etherdevice.h>
+ #include <linux/acpi.h>
+@@ -8390,6 +8391,7 @@ int ath10k_mac_register(struct ath10k *a
+ 		ar->hw->wiphy->bands[NL80211_BAND_5GHZ] = band;
+ 	}
+ 
++	wiphy_read_of_freq_limits(ar->hw->wiphy);
+ 	ath10k_mac_setup_ht_vht_cap(ar);
+ 
+ 	ar->hw->wiphy->interface_modes =