Handle sample rate out of bound correctly.

This CL changes the behavior when sample rate is out of bound
for VHAL. Sample rate would be fitted to the range if out-of-bound.
Also added some comments to clearly document this behavior.

Test: atest DefaultVehicleHalTest
atest CtsCarTestCases
Bug: 225025926

Change-Id: Id853070cb0dc823855a68f86a01de2ff2a011577