mac80211: silence warning for missing rate information

Silence warnings for missing rate information.

These warnings do not provide value. Instead, they might rotate more
crucial information out of the kernel message ringbuffer.

Link: #3160

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

patches/openwrt/0007-mac80211-silence-warning-for-missing-rate-information.patch

@@ -0,0 +1,30 @@
+From: David Bauer <mail@david-bauer.net>
+Date: Thu, 18 Jan 2024 00:52:09 +0100
+Subject: mac80211: silence warning for missing rate information
+
+Silence warnings for missing rate information.
+
+These warnings do not provide value. Instead, they might rotate more
+crucial information out of the kernel message ringbuffer.
+
+Link: https://github.com/freifunk-gluon/gluon/issues/3160
+
+Signed-off-by: David Bauer <mail@david-bauer.net>
+
+diff --git a/package/kernel/mac80211/patches/subsys/999-silence-missing-rate.patch b/package/kernel/mac80211/patches/subsys/999-silence-missing-rate.patch
+new file mode 100644
+index 0000000000000000000000000000000000000000..a34455f78960ded59b60d3d9600823b39fc7b7a2
+--- /dev/null
++++ b/package/kernel/mac80211/patches/subsys/999-silence-missing-rate.patch
+@@ -0,0 +1,11 @@
++--- a/net/mac80211/mesh_hwmp.c
+++++ b/net/mac80211/mesh_hwmp.c
++@@ -350,7 +350,7 @@ u32 airtime_link_metric_get(struct ieee8
++ 			return MAX_METRIC;
++ 
++ 		rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
++-		if (WARN_ON(!rate))
+++		if (!rate)
++ 			return MAX_METRIC;
++ 
++ 		err = (fail_avg << ARITH_SHIFT) / 100;