The T4240RDB contains a W83793 hardware monitoring chip. Add a device
tree entry to make the driver attach to it, as the i2c-mpc bus driver
dropped support for class-based instantiation of devices a long time
ago.
Signed-off-by: Florian Larysch <fl@n621.de> Signed-off-by: Scott Wood <oss@buserror.net>