ALSA: pcm_dmaengine: Use the available wrapper to get physical width

params_physical_width() is available via pcm_params.h

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@linaro.org>