net: ksz9477: remove dev_set_parent_priv() call

net: ksz9477: remove dev_set_parent_priv() call

The ksz9477 is currently the only driver using dev_set_parent_priv()
outside of the driver model. Also, there was no explanation in the
commit adding ksz9477 driver and why dev_set_parent_priv() is
required.

Actually there is a typo in ksz_mdio_probe() while retrieving
the parent (switch@0) private data:

-	priv->ksz = dev_get_parent_priv(dev->parent);
+	priv->ksz = dev_get_priv(dev->parent);

Printing the address of struct ksz_dsa_priv *priv allows
to notice the slight difference:

ksz_i2c_probe: ksz_dsa_priv *priv 0xfdf45768 // address of the saved priv
ksz_mdio_bind: ksz_dsa_priv *priv 0xfdf45798 // address returned by dev_get_parent_priv(dev->parent)
ksz_mdio_bind: ksz_dsa_priv *priv 0xfdf45768 // address returned by dev_get_priv(dev->parent)

The ksz_mdio driver get the wrong data and without
dev_set_parent_priv() the mdio driver fail to access the underlying
bus.

While it doesn't cause any issue with I2C bus, it override the
per-child data used by the SPI bus (struct spi_slave) and prevent
further bus access (even with sspi command).

Signed-off-by: Romain Naour <romain.naour@smile.fr>