sfc: Generate RX fill events based on RX queues, not channels

This makes it harder to accidentally send such events to TX-only
channels.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 1dfda5e..76fb521 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -405,10 +405,9 @@
 void efx_rx_slow_fill(unsigned long context)
 {
 	struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context;
-	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
 
 	/* Post an event to cause NAPI to run and refill the queue */
-	efx_nic_generate_fill_event(channel);
+	efx_nic_generate_fill_event(rx_queue);
 	++rx_queue->slow_fill_count;
 }