atl1: zero out CMB and SBM in atl1_free_ring_resources

They are allocated in atl1_setup_ring_resources, zero out the pointers
in atl1_free_ring_resources (like the other resources).
Signed-off-by: NLuca Tettamanti <kronos.it@gmail.com>
Acked-by: NChris Snook <chris.snook@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/atlx/atl1.c

@@ -1251,6 +1251,12 @@ static void atl1_free_ring_resources(struct atl1_adapter *adapter)
 
 	rrd_ring->desc = NULL;
 	rrd_ring->dma = 0;
+
+	adapter->cmb.dma = 0;
+	adapter->cmb.cmb = NULL;
+
+	adapter->smb.dma = 0;
+	adapter->smb.smb = NULL;
 }
 
 static void atl1_setup_mac_ctrl(struct atl1_adapter *adapter)