net: bcmgenet: drop checks on priv->phydev

Drop all the checks on priv->phydev since we will refuse probing the
driver if we cannot attach to a PHY device. Drop all checks on
priv->phydev. This also fixes some smatch issues reported by Dan
Carpenter.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>