wifi: wext: warn about usage only once

Warn only once since the ratelimit parameters are still
allowing too many messages to happen. This will no longer
tell you all the different processes, but still gives a
heads-up of sorts.

Also modify the message to note that wext stops working
for future Wi-Fi 7 hardware, this is already implemented
in commit 4ca6902 ("wifi: wireless: deny wireless
extensions on MLO-capable devices") and is maybe of more
relevance to users than the fact that we'd like to have
wireless extensions deprecated.

The issue with Wi-Fi 7 is that you can now have multiple
connections to the same AP, so a whole bunch of things
now become per link rather than per netdev, which can't
really be handled in wireless extensions.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230224135933.94104aeda1a0.Ie771c6a66d7d6c3cf67da5f3b0c66cea66fd514c@changeid

net/wireless/wext-core.c

@@ -641,8 +641,8 @@ static void wireless_warn_cfg80211_wext(void)
 {
 	char name[sizeof(current->comm)];
 
-	pr_warn_ratelimited("warning: `%s' uses wireless extensions that are deprecated for modern drivers; use nl80211\n",
-			    get_task_comm(name, current));
+	pr_warn_once("warning: `%s' uses wireless extensions which will stop working for Wi-Fi 7 hardware; use nl80211\n",
+		     get_task_comm(name, current));
 }
 #endif