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/fsl_pq_mdio.c b/drivers/net/ethernet/freescale/fsl_pq_mdio.c
index d1a91e3..3c40f6b 100644
--- a/drivers/net/ethernet/freescale/fsl_pq_mdio.c
+++ b/drivers/net/ethernet/freescale/fsl_pq_mdio.c
@@ -294,7 +294,7 @@
 
 #endif
 
-static struct of_device_id fsl_pq_mdio_match[] = {
+static const struct of_device_id fsl_pq_mdio_match[] = {
 #if defined(CONFIG_GIANFAR) || defined(CONFIG_GIANFAR_MODULE)
 	{
 		.compatible = "fsl,gianfar-tbi",