staging: rtl8723bs: reduce stack usage of rtw_cfg80211_unlink_bss

The build of xtensa allmodconfig gives warning of:
In function 'rtw_cfg80211_unlink_bss':
warning: the frame size of 1136 bytes is larger than 1024 bytes

Instead of having 'select_network' structure as a variable use it as a
pointer.
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20191018104837.23246-1-sudipm.mukherjee@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c

@@ -1410,16 +1410,17 @@ void rtw_cfg80211_unlink_bss(struct adapter *padapter, struct wlan_network *pnet
 	struct wireless_dev *pwdev = padapter->rtw_wdev;
 	struct wiphy *wiphy = pwdev->wiphy;
 	struct cfg80211_bss *bss = NULL;
-	struct wlan_bssid_ex select_network = pnetwork->network;
+	struct wlan_bssid_ex *select_network = &pnetwork->network;
 
 	bss = cfg80211_get_bss(wiphy, NULL/*notify_channel*/,
-		select_network.MacAddress, select_network.Ssid.Ssid,
-		select_network.Ssid.SsidLength, 0/*WLAN_CAPABILITY_ESS*/,
+		select_network->MacAddress, select_network->Ssid.Ssid,
+		select_network->Ssid.SsidLength, 0/*WLAN_CAPABILITY_ESS*/,
 		0/*WLAN_CAPABILITY_ESS*/);
 
 	if (bss) {
 		cfg80211_unlink_bss(wiphy, bss);
-		DBG_8192C("%s(): cfg80211_unlink %s!! () ", __func__, select_network.Ssid.Ssid);
+		DBG_8192C("%s(): cfg80211_unlink %s!! () ", __func__,
+			  select_network->Ssid.Ssid);
 		cfg80211_put_bss(padapter->rtw_wdev->wiphy, bss);
 	}
 }