sfc: track which BAR is mapped

EF100 needs to map multiple BARs (sequentially, not concurrently) in
 order to read the Function Control Window during probe.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/net_driver.h

@@ -961,6 +961,7 @@ struct efx_async_filter_insertion {
  * @vpd_sn: Serial number read from VPD
  * @xdp_rxq_info_failed: Have any of the rx queues failed to initialise their
  *      xdp_rxq_info structures?
+ * @mem_bar: The BAR that is mapped into membase.
  * @monitor_work: Hardware monitor workitem
  * @biu_lock: BIU (bus interface unit) lock
  * @last_irq_cpu: Last CPU to handle a possible test interrupt.  This
@@ -1137,6 +1138,8 @@ struct efx_nic {
 	char *vpd_sn;
 	bool xdp_rxq_info_failed;
 
+	unsigned int mem_bar;
+
 	/* The following fields may be written more often */
 
 	struct delayed_work monitor_work ____cacheline_aligned_in_smp;