phy: lynx-28g: require an OF node to probe

phy: lynx-28g: require an OF node to probe

The driver will gain support for variants in an upcoming change, and
will use of_device_get_match_data() to deduce the running variant from
the compatible string.

Currently, the driver expects the schema at phy/fsl,lynx-28g.yaml, and
OF-based consumers, but doesn't enforce this. And it is possible for
user space to force-bind the driver to a device without OF node using
the driver_override sysfs.

To avoid future surprise crashes for an unsupported configuration,
explicitly test for the presence of an OF node and fail probing if
found.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Tested-by: Josua Mayer <josua@solid-run.com>
Link: https://patch.msgid.link/20260511150023.1903577-4-vladimir.oltean@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>