sfc: Allow efx_channel_type::receive_skb() to reject a packet

Instead of having efx_ptp_rx() call netif_receive_skb() for an invalid
PTP packet, make it return false for rejected packets and have
efx_rx_deliver() pass them up.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 0a90abd..cdcf510 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -410,7 +410,7 @@
 	void (*post_remove)(struct efx_channel *);
 	void (*get_name)(struct efx_channel *, char *buf, size_t len);
 	struct efx_channel *(*copy)(const struct efx_channel *);
-	void (*receive_skb)(struct efx_channel *, struct sk_buff *);
+	bool (*receive_skb)(struct efx_channel *, struct sk_buff *);
 	bool keep_eventq;
 };