net: phy: microchip_t1s: modify driver description to be more generic

Remove LAN867X from the driver description as this driver is common for
all the Microchip 10BASE-T1S PHYs.

Reviewed-by: Ramón Nordin Rodriguez <ramon.nordin.rodriguez@ferroamp.se>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>