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/efx.c b/drivers/net/sfc/efx.c
index 05502b3..c914729 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -833,7 +833,7 @@
 	}
 }
 
-void efx_link_set_wanted_fc(struct efx_nic *efx, enum efx_fc_type wanted_fc)
+void efx_link_set_wanted_fc(struct efx_nic *efx, u8 wanted_fc)
 {
 	efx->wanted_fc = wanted_fc;
 	if (efx->link_advertising) {