fakehard: no need to export net_to_phy, make it static

#include <net/nl802154.h>

#include <net/wpan-phy.h>

struct wpan_phy *net_to_phy(struct net_device *dev)

static struct wpan_phy *net_to_phy(struct net_device *dev)

{

	return container_of(dev->dev.parent, struct wpan_phy, dev);

}