ASoC: fsl-ssi: Move RX/TX configuration to seperate functions

This patch defines the appropriate register values for different
oparation modes and IP versions. We have to handle DMA/FIQ, AC97,
DEBUG-IRQs and offline/online configuration support.

With this patch we cleanup some driver code that was not reference
manual conform and try to cleanup the whole trigger function to seperate
the actual register values from the enable/disable logic, which is now
hidden in fsl_ssi_config helpers.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>