net: lan966x: allow offloading timestamp operations to the PHY

In case the MAC is using 'netif_rx()' to deliver the skb up the network
stack, it needs to check whether 'skb_defer_rx_timestmap()' is necessary
or not. In case is needed then don't call 'netif_rx()'

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20220307094632.3764266-1-horatiu.vultur@microchip.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

@@ -600,7 +600,9 @@ static irqreturn_t lan966x_xtr_irq_handler(int irq, void *args)
 				skb->offload_fwd_mark = 0;
 		}
 
-		netif_rx(skb);
+		if (!skb_defer_rx_timestamp(skb))
+			netif_rx(skb);
+
 		dev->stats.rx_bytes += len;
 		dev->stats.rx_packets++;