staging: r8188eu: replace one GetAddr3Ptr call

Define a struct ieee80211_mgmt in the OnBeacon function. Use it to replace
one GetAddr3Ptr call. This is a tiny step towards making GetAddr3Ptr
obsolete.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221126160129.178697-2-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_mlme_ext.c

@@ -560,6 +560,7 @@ static void OnProbeRsp(struct adapter *padapter, struct recv_frame *precv_frame)
 
 static void OnBeacon(struct adapter *padapter, struct recv_frame *precv_frame)
 {
+	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)precv_frame->rx_data;
 	int cam_idx;
 	struct sta_info	*psta;
 	struct mlme_ext_priv	*pmlmeext = &padapter->mlmeextpriv;
@@ -576,7 +577,7 @@ static void OnBeacon(struct adapter *padapter, struct recv_frame *precv_frame)
 		return;
 	}
 
-	if (!memcmp(GetAddr3Ptr(pframe), get_my_bssid(&pmlmeinfo->network), ETH_ALEN)) {
+	if (!memcmp(mgmt->bssid, get_my_bssid(&pmlmeinfo->network), ETH_ALEN)) {
 		if (pmlmeinfo->state & WIFI_FW_AUTH_NULL) {
 			/* we should update current network before auth, or some IE is wrong */
 			pbss = kmalloc(sizeof(struct wlan_bssid_ex), GFP_ATOMIC);