wifi: mac80211: allow CSA to same channel

This could be used e.g. for temporarily sending quiet
(mode=1 in CSA/ECSA), or updating bandwidth. This is
also useful for testing, since it's something that an
AP may do and the client needs to be prepared. Simply
allow it.

Link: https://msgid.link/20240129203544.ef7258d5790d.Idafe22e41621757458d4960659b9621853f7104d@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -3876,10 +3876,6 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 	if (sdata->wdev.cac_started)
 		return -EBUSY;
 
-	if (cfg80211_chandef_identical(&chanreq.oper,
-				       &sdata->vif.bss_conf.chanreq.oper))
-		return -EINVAL;
-
 	if (chanreq.oper.punctured && !sdata->vif.bss_conf.eht_support)
 		return -EINVAL;