qcacld-3.0: Fix monitor mode initialization failure on Helium

Returning a negative value from the API results in the failure
on unsupported platform.

CRs-Fixed: 2082239
Change-Id: I75b14b81eaa00d53784a6deb90b99666e28b164d

core/hdd/src/wlan_hdd_rx_monitor.h

@@ -47,7 +47,7 @@ static inline void hdd_rx_monitor_callback(ol_osif_vdev_handle vdev,
 				void *rx_status){ }
 static inline int hdd_enable_monitor_mode(struct net_device *dev)
 {
-	return -ENOSYS;
+	return 0;
 }
 #endif /* CONFIG_LITHIUM */