aaudio: restore _get and _setSamplesPerFrame()

This restores some deprecated functions that some released apps
were calling. Restored:

    AAudioStreamBuilder_setSamplesPerFrame()
    AAudioStream_getSamplesPerFrame()

Bug: 64346279
Test: put GStomper in AAudio mode using its Settings on Marlin
Change-Id: I2749a06cded9fc3863d233713efda2674cf7f5e3