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/mac.h b/drivers/net/sfc/mac.h
index 6886cdf..d6a255d 100644
--- a/drivers/net/sfc/mac.h
+++ b/drivers/net/sfc/mac.h
@@ -13,8 +13,8 @@
 
 #include "net_driver.h"
 
-extern struct efx_mac_operations falcon_xmac_operations;
-extern struct efx_mac_operations efx_mcdi_mac_operations;
+extern const struct efx_mac_operations falcon_xmac_operations;
+extern const struct efx_mac_operations efx_mcdi_mac_operations;
 extern int efx_mcdi_mac_stats(struct efx_nic *efx, dma_addr_t dma_addr,
 			      u32 dma_len, int enable, int clear);