alsa_sound: only use resampler when defined

*Resampler was causing issues with a2dp on d2's
This removes the use of it and in combination with hardcoded 48k sampling rate,
allows for clean and clear playback on a2dp.

*To use resampler define BOARD_USES_RESAMPLER := true in BoardConfig

Change-Id: I1dc1527cdabf42ec1e1629e4cd49148424ed9bac
Signed-off-by: bmc08gt <bmc08gt.teamb00sted@gmail.com>