of: of_mdio: Ensure mdio device is a PHY

of_phy_find_device() is used to find the phy device associated with a
device node. It is expected the node is for a PHY device, but in fact
it could of been probed as a generic MDIO device. Ensure the device is
a PHY before returning it.

Fixes: a9049e0c513c ("mdio: Add support for mdio drivers.")
Reported-by: Aaro Koskinen <[email protected]>
Reported-by: Olof Johansson <[email protected]>
Signed-off-by: Andrew Lunn <[email protected]>
Tested-by: Aaro Koskinen <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
1 file changed