ASoC: dmaengine: Remove unnecessary snd_pcm_lib_preallocate_free_for_all()

The ALSA core takes care that all preallocated memory is freed when the PCM
itself is freed. There is no need to do this manually in the driver.
Similarly there is also no need to do it on the pcm_new() error path as the
PCM will be freed if a error is returned.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>