Use absolute frequency in WaveformBuilder

Remove the concept of relative frequency and the mapping logic from
VibratorInfo and receive absolute frequency values, in hertz, from
WaveformBuilder.

The clipping logic to make all PWLE amplitudes fit the HAL bandwidth map
still remains.

Bug: 203785430
Test: com.android.server.vibrator.*
Change-Id: Ic01a08d84e66d88acad6db5c704251394afbf1f6