ASoC: qcom: use snd_dma_alloc/free* apis

There is no point in having local allocation functions when the driver
can use snd_dma_alloc/free() apis. This patch replaces the local versions
of the dma allocation apis with the snd_dma_alloc/free() apis.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>