hwmon: (tps23861) correct shunt LSB values

Current shunt LSB values got reversed during in the
original driver commit.

So, correct the current shunt LSB values according to
the datasheet.

This caused reading slightly skewed current values.

Fixes: fff7b8ab

 ("hwmon: add Texas Instruments TPS23861 driver")
Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Link: https://lore.kernel.org/r/20210609220728.499879-3-robert.marko@sartura.hr


Signed-off-by: Guenter Roeck <linux@roeck-us.net>