ASoC: fsl: fsl_asrc: Select SND_SOC_GENERIC_DMAENGINE_PCM

Building a kernel with SND_SOC_GENERIC_DMAENGINE_PCM=n leads to the following
error:

ERROR: "snd_dmaengine_pcm_prepare_slave_config" [sound/soc/fsl/snd-soc-fsl-asrc.ko] undefined!

Let SND_SOC_FSL_ASRC select SND_SOC_GENERIC_DMAENGINE_PCM in order to fix such
error.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>