staging: wlan-ng: cfg80211: Move large struct onto the heap

Fixes the following W=1 kernel build warning(s):

drivers/staging/wlan-ng/cfg80211.c: In function ‘prism2_scan’:
drivers/staging/wlan-ng/cfg80211.c:388:1: warning: the frame size of 1296 bytes is larger than 1024 bytes [-Wframe-larger-than=]

Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Sumera Priyadarsini <[e-mail]>
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/wlan-ng/cfg80211.c

···
 	struct prism2_wiphy_private *priv = wiphy_priv(wiphy);
 	struct wlandevice *wlandev;
 	struct p80211msg_dot11req_scan msg1;
-	struct p80211msg_dot11req_scan_results msg2;
+	struct p80211msg_dot11req_scan_results *msg2;
 	struct cfg80211_bss *bss;
 	struct cfg80211_scan_info info = {};
 
···
 		netdev_err(dev, "Can't scan in AP mode\n");
 		return -EOPNOTSUPP;
 	}
+
+	msg2 = kzalloc(sizeof(*msg2), GFP_KERNEL);
+	if (!msg2)
+		return -ENOMEM;
 
 	priv->scan_request = request;
 
···
 	for (i = 0; i < numbss; i++) {
 		int freq;
 
-		memset(&msg2, 0, sizeof(msg2));
-		msg2.msgcode = DIDMSG_DOT11REQ_SCAN_RESULTS;
-		msg2.bssindex.data = i;
+		msg2->msgcode = DIDMSG_DOT11REQ_SCAN_RESULTS;
+		msg2->bssindex.data = i;
 
 		result = p80211req_dorequest(wlandev, (u8 *)&msg2);
 		if ((result != 0) ||
-		    (msg2.resultcode.data != P80211ENUM_resultcode_success)) {
+		    (msg2->resultcode.data != P80211ENUM_resultcode_success)) {
 			break;
 		}
 
 		ie_buf[0] = WLAN_EID_SSID;
-		ie_buf[1] = msg2.ssid.data.len;
+		ie_buf[1] = msg2->ssid.data.len;
 		ie_len = ie_buf[1] + 2;
-		memcpy(&ie_buf[2], &msg2.ssid.data.data, msg2.ssid.data.len);
-		freq = ieee80211_channel_to_frequency(msg2.dschannel.data,
+		memcpy(&ie_buf[2], &msg2->ssid.data.data, msg2->ssid.data.len);
+		freq = ieee80211_channel_to_frequency(msg2->dschannel.data,
 						      NL80211_BAND_2GHZ);
 		bss = cfg80211_inform_bss(wiphy,
 					  ieee80211_get_channel(wiphy, freq),
 					  CFG80211_BSS_FTYPE_UNKNOWN,
-					  (const u8 *)&msg2.bssid.data.data,
-					  msg2.timestamp.data, msg2.capinfo.data,
-					  msg2.beaconperiod.data,
+					  (const u8 *)&msg2->bssid.data.data,
+					  msg2->timestamp.data, msg2->capinfo.data,
+					  msg2->beaconperiod.data,
 					  ie_buf,
 					  ie_len,
-					  (msg2.signal.data - 65536) * 100, /* Conversion to signed type */
+					  (msg2->signal.data - 65536) * 100, /* Conversion to signed type */
 					  GFP_KERNEL);
 
 		if (!bss) {
···
 	}
 
 	if (result)
-		err = prism2_result2err(msg2.resultcode.data);
+		err = prism2_result2err(msg2->resultcode.data);
 
 exit:
 	info.aborted = !!(err);
 	cfg80211_scan_done(request, &info);
 	priv->scan_request = NULL;
+	kfree(msg2);
 	return err;
 }