qcacld-3.0: Optimize string log size in hdd_rssi_threshold_breached

Optimize string log size in hdd API hdd_rssi_threshold_breached such
that wlan.ko size is optimized.

Change-Id: I71fb6fc8e9f71e52b11dc67aeec58095555eceaf
CRs-Fixed: 2271644

core/hdd/src/wlan_hdd_cfg80211.c

@@ -8441,7 +8441,7 @@ void hdd_rssi_threshold_breached(void *hddctx,
 				  GFP_KERNEL);
 
 	if (!skb) {
-		hdd_err("cfg80211_vendor_event_alloc failed");
+		hdd_err("mem alloc failed");
 		return;
 	}