netdev: octeon_mgmt: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/octeon/octeon_mgmt.c b/drivers/net/ethernet/octeon/octeon_mgmt.c
index d36599f..7bf9c02 100644
--- a/drivers/net/ethernet/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/octeon/octeon_mgmt.c
@@ -1557,7 +1557,7 @@
 	return 0;
 }
 
-static struct of_device_id octeon_mgmt_match[] = {
+static const struct of_device_id octeon_mgmt_match[] = {
 	{
 		.compatible = "cavium,octeon-5750-mix",
 	},