Since phy driver features became a link_mode bitmap, phy drivers that
don't have a list of features configured will cause the kernel to crash
when probed.
Prevent the phy driver from registering if the features field is missing.
Fixes: 719655a14971 ("net: phy: Replace phy driver features u32 with link_mode bitmap")
Reported-by: Scott Wood <oss@buserror.net>
Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 {
        int retval;
 
+       if (WARN_ON(!new_driver->features)) {
+               pr_err("%s: Driver features are missing\n", new_driver->name);
+               return -EINVAL;
+       }
+
        new_driver->mdiodrv.flags |= MDIO_DEVICE_IS_PHY;
        new_driver->mdiodrv.driver.name = new_driver->name;
        new_driver->mdiodrv.driver.bus = &mdio_bus_type;
 
  *   only works for PHYs with IDs which match this field
  * name: The friendly name of this PHY type
  * phy_id_mask: Defines the important bits of the phy_id
- * features: A list of features (speed, duplex, etc) supported
- *   by this PHY
+ * features: A mandatory list of features (speed, duplex, etc)
+ *   supported by this PHY
  * flags: A bitfield defining certain other features this PHY
  *   supports (like interrupts)
  *