wifi: cfg80211: avoid leaking stack data into trace

If the structure is not initialized then boolean types might be copied
into the tracing data without being initialised. This causes data from
the stack to leak into the trace and also triggers a UBSAN failure which
can easily be avoided here.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://lore.kernel.org/r/20230925171855.a9271ef53b05.I8180bae663984c91a3e036b87f36a640ba409817@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -8501,7 +8501,7 @@ static int nl80211_update_mesh_config(struct sk_buff *skb,
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
-	struct mesh_config cfg;
+	struct mesh_config cfg = {};
 	u32 mask;
 	int err;