sfc: Don't use enums as a bitmask.

This fixes:

drivers/net/sfc/mcdi_mac.c: In function ‘efx_mcdi_set_mac’:
drivers/net/sfc/mcdi_mac.c:36:2: warning: case value ‘3’ not in enumerated type ‘enum efx_fc_type’

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 348437a..d229027 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -698,7 +698,7 @@
 				      struct ethtool_pauseparam *pause)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
-	enum efx_fc_type wanted_fc, old_fc;
+	u8 wanted_fc, old_fc;
 	u32 old_adv;
 	bool reset;
 	int rc = 0;