lan743x: Enable driver to work with LAN7431

lan743x: Enable driver to work with LAN7431

[ Upstream commit 4df5ce9bc03e47d05f400e64aa32a82ec4cef419 ]

This driver was designed to work with both LAN7430 and LAN7431.
The only difference between the two is the LAN7431 has support
for external phy.

This change adds LAN7431 to the list of recognized devices
supported by this driver.

Updates for v2:
    changed 'fixes' tag to match defined format

fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver")
Signed-off-by: Bryan Whitehead <Bryan.Whitehead@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>