ASoC: tegra: correct playback_dma_data setup

The errors were caused by copy/paste mistake in below commit
since v3.10:
3489d50 ASoC: tegra: Use common DAI DMA data struct

It also corrects slave_id initialization in tegra20_ac97 driver.

Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: <stable@vger.kernel.org> # 3.10