Only requantize sensor max range if significant

The previous computation that decided whether to adjust the sensor's
reported maximum range if not a multiple of the resolution was
susceptible to floating point error (e.g. considering 5.0 as not a
multiple of 0.1), so rework this to only update the maximum range and
print a warning log if the maximum range would be changed significantly
after requantization. We define significant here as resolution/8 (i.e.
the target quantization level).

Also, make the reported power clamping log more helpful.

Fixes: 182828004
Test: compare SensorService startup logs before & after change
Change-Id: I44e399a7aca6fe8ff02bd2840525c95798cda1f4