net/fsl: 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/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 70fa688..4ee080d 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -3594,7 +3594,7 @@
 		phy_print_status(phydev);
 }
 
-static struct of_device_id gfar_match[] =
+static const struct of_device_id gfar_match[] =
 {
 	{
 		.type = "network",