Use SENSORS_DEVICE_ATTR instead of DEVICE_ATTR for most attributes,
so that the attribute number can be retrieved and it is no longer
necessary to generate functions using macros.

This shaves about 2 kB on the binary module size.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>