phy: make phy_connect_fixed work with a null mdio bus

It is utterly pointless to require an MDIO bus pointer for a fixed PHY
device. The fixed.c implementation does not require it, only
phy_device_create. Fix that.
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NHou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

drivers/net/phy/phy.c

@@ -664,7 +664,7 @@ static struct phy_device *phy_device_create(struct mii_dev *bus, int addr,
 	dev = malloc(sizeof(*dev));
 	if (!dev) {
 		printf("Failed to allocate PHY device for %s:%d\n",
-		       bus->name, addr);
+		       bus ? bus->name : "(null bus)", addr);
 		return NULL;
 	}
 
@@ -692,7 +692,7 @@ static struct phy_device *phy_device_create(struct mii_dev *bus, int addr,
 		return NULL;
 	}
 
-	if (addr >= 0 && addr < PHY_MAX_ADDR)
+	if (addr >= 0 && addr < PHY_MAX_ADDR && phy_id != PHY_FIXED_ID)
 		bus->phymap[addr] = dev;
 
 	return dev;