wandboard: Fix sparse warning

Add a prototype for board_phy_config() to fix the following sparse warning:

wandboard.c:200:5: warning: symbol 'board_phy_config' was not declared. Should it be static?

Cc: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

board/wandboard/wandboard.c

@@ -25,6 +25,7 @@
 #include <miiphy.h>
 #include <netdev.h>
 #include <linux/fb.h>
+#include <phy.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 

include/phy.h

@@ -234,6 +234,8 @@ int phy_smsc_init(void);
 int phy_teranetics_init(void);
 int phy_vitesse_init(void);
 
+int board_phy_config(struct phy_device *phydev);
+
 /* PHY UIDs for various PHYs that are referenced in external code */
 #define PHY_UID_TN2020	0x00a19410