sfc: don't report RX hash keys to ethtool when RSS wasn't enabled

If we failed to set up RSS on EF10 (e.g. because firmware declared
 RX_RSS_LIMITED), ethtool --show-nfc $dev rx-flow-hash ... should report
 no fields, rather than confusingly reporting what fields we _would_ be
 hashing on if RSS was working.

Fixes: dcb4123cbec0 ("sfc: disable RSS when unsupported")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 1a635ce..1c62c1a 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -860,6 +860,7 @@ struct vfdi_status;
  * @rx_hash_key: Toeplitz hash key for RSS
  * @rx_indir_table: Indirection table for RSS
  * @rx_scatter: Scatter mode enabled for receives
+ * @rss_active: RSS enabled on hardware
  * @rx_hash_udp_4tuple: UDP 4-tuple hashing enabled
  * @int_error_count: Number of internal errors seen recently
  * @int_error_expire: Time at which error count will be expired
@@ -998,6 +999,7 @@ struct efx_nic {
 	u8 rx_hash_key[40];
 	u32 rx_indir_table[128];
 	bool rx_scatter;
+	bool rss_active;
 	bool rx_hash_udp_4tuple;
 
 	unsigned int_error_count;