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/mcdi_mac.c b/drivers/net/sfc/mcdi_mac.c
index 33f7294..50c2077 100644
--- a/drivers/net/sfc/mcdi_mac.c
+++ b/drivers/net/sfc/mcdi_mac.c
@@ -138,7 +138,7 @@
 }
 
 
-struct efx_mac_operations efx_mcdi_mac_operations = {
+const struct efx_mac_operations efx_mcdi_mac_operations = {
 	.reconfigure	= efx_mcdi_mac_reconfigure,
 	.update_stats	= efx_port_dummy_op_void,
 	.check_fault 	= efx_mcdi_mac_check_fault,