Currently each channel can have at most one RX queue, so go straight to
that one.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
 
 /* Iterate over all RX queues belonging to a channel */
 #define efx_for_each_channel_rx_queue(_rx_queue, _channel)             \
-       for (_rx_queue = &_channel->efx->rx_queue[0];                   \
-            _rx_queue < &_channel->efx->rx_queue[EFX_MAX_RX_QUEUES];   \
-            _rx_queue++)                                               \
+       for (_rx_queue = &_channel->efx->rx_queue[_channel->channel];   \
+            _rx_queue;                                                 \
+            _rx_queue = NULL)                                          \
                if (_rx_queue->channel != _channel)                     \
                        continue;                                       \
                else