net: dsa: xrs700x: use of_match_ptr() on xrs700x_mdio_dt_ids

Use of_match_ptr() on xrs700x_mdio_dt_ids so that NULL is substituted
when CONFIG_OF isn't defined. This will prevent unnecessary use of
xrs700x_mdio_dt_ids when CONFIG_OF isn't defined.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/xrs700x/xrs700x_mdio.c b/drivers/net/dsa/xrs700x/xrs700x_mdio.c
index 3b3b78f..44f58be 100644
--- a/drivers/net/dsa/xrs700x/xrs700x_mdio.c
+++ b/drivers/net/dsa/xrs700x/xrs700x_mdio.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/phy.h>
 #include <linux/if_vlan.h>
+#include <linux/of.h>
 #include "xrs700x.h"
 #include "xrs700x_reg.h"
 
@@ -150,7 +151,7 @@ MODULE_DEVICE_TABLE(of, xrs700x_mdio_dt_ids);
 static struct mdio_driver xrs700x_mdio_driver = {
 	.mdiodrv.driver = {
 		.name	= "xrs700x-mdio",
-		.of_match_table = xrs700x_mdio_dt_ids,
+		.of_match_table = of_match_ptr(xrs700x_mdio_dt_ids),
 	},
 	.probe	= xrs700x_mdio_probe,
 	.remove	= xrs700x_mdio_remove,