Use resolution to round sensor event values

Add method to utilize a sensor's specified resolution value to ensure
data isn't provided that is more fine-grained than expected. This
helps mitigate sensor calibration fingerprinting attacks.

Bug: 147725937
Test: Verify accel sensor data isn't more fine grained than its
specified resolution

Change-Id: I81905cde22cc8429021ffb8318a222512ce01900