sfc: make function tables const

The phy, mac, and board information structures should be const.
Since tables contain function pointer this improves security
(at least theoretically).

Compile tested only.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/falcon_xmac.c b/drivers/net/sfc/falcon_xmac.c
index 2c9ee5d..9516452 100644
--- a/drivers/net/sfc/falcon_xmac.c
+++ b/drivers/net/sfc/falcon_xmac.c
@@ -362,7 +362,7 @@
 	falcon_ack_status_intr(efx);
 }
 
-struct efx_mac_operations falcon_xmac_operations = {
+const struct efx_mac_operations falcon_xmac_operations = {
 	.reconfigure	= falcon_reconfigure_xmac,
 	.update_stats	= falcon_update_stats_xmac,
 	.check_fault	= falcon_xmac_check_fault,