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/siena.c b/drivers/net/sfc/siena.c
index e4dd898..ceac1c9 100644
--- a/drivers/net/sfc/siena.c
+++ b/drivers/net/sfc/siena.c
@@ -581,7 +581,7 @@
  **************************************************************************
  */
 
-struct efx_nic_type siena_a0_nic_type = {
+const struct efx_nic_type siena_a0_nic_type = {
 	.probe = siena_probe_nic,
 	.remove = siena_remove_nic,
 	.init = siena_init_nic,