Add datasheet reference and device ID for ADT75.

The ADT75, like some other LM75 derivatives, needs to be instantiated
using methods 1, 2, or 4.
For more information see Documentation/i2c/instantiating-devices.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>