wifi: mac80211: ocb: skip rx_no_sta when interface is not joined

ieee80211_ocb_rx_no_sta() assumes a valid channel context, which is only
present after JOIN_OCB.

RX may run before JOIN_OCB is executed, in which case the OCB interface
is not operational. Skip RX peer handling when the interface is not
joined to avoid warnings in the RX path.

Reported-by: [e-mail]
Closes: https://syzkaller.appspot.com/bug?extid=b364457b2d1d4e4a3054
Tested-by: [e-mail]
Signed-off-by: Moon Hee Lee <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

net/mac80211/ocb.c

···
 	struct sta_info *sta;
 	int band;
 
+	if (!ifocb->joined)
+		return;
+
 	/* XXX: Consider removing the least recently used entry and
 	 *      allow new one to be added.
 	 */