hostapd: Fix handling a 20/40 BSS Coexistence Management frame

hostapd processes a received 20/40 BSS Coexistence management frame, but
if no separate callbacks are registered for handling Public Action
frames it eventually sends a reply with MSB of category code set to 1
thinking that the received frame is an invalid frame. This could happen
based on whether hostapd was built and enabled with functionality using
the callback functions.

Fix this by explicitly returning 1 from the function when the 20/40 BSS
Coexistence Management frame is processed.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/ieee802_11.c

@@ -3448,6 +3448,7 @@ static int handle_action(struct hostapd_data *hapd,
 				   "HT20/40 coex mgmt frame received from STA "
 				   MACSTR, MAC2STR(mgmt->sa));
 			hostapd_2040_coex_action(hapd, mgmt, len);
+			return 1;
 		}
 #endif /* CONFIG_IEEE80211N */
 		if (hapd->public_action_cb) {