wifi: rtw89: check return value of ieee80211_probereq_get() for RNR

The return value of ieee80211_probereq_get() might be NULL, so check it
before using to avoid NULL pointer access.

Addresses-Coverity-ID: 1529805 ("Dereference null return value")

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240919081216.28505-2-pkshih@realtek.com

Author: Ping-Ke Shih

drivers/net/wireless/realtek/rtw89/fw.c

@@ -6089,6 +6089,9 @@ static int rtw89_update_6ghz_rnr_chan(struct rtw89_dev *rtwdev,
 
 		skb = ieee80211_probereq_get(rtwdev->hw, rtwvif_link->mac_addr,
 					     NULL, 0, req->ie_len);
+		if (!skb)
+			return -ENOMEM;
+
 		skb_put_data(skb, ies->ies[NL80211_BAND_6GHZ], ies->len[NL80211_BAND_6GHZ]);
 		skb_put_data(skb, ies->common_ies, ies->common_ie_len);
 		hdr = (struct ieee80211_hdr *)skb->data;