net: of_mdio: use PHY_MAX_ADDR constant

Use the PHY_MAX_ADDR constant for checking if a MDIO bus address is
valid instead of using a plain "32".

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed