When application goes through SUSPEND/STOP->PREPARE->START
cycle, we should always reprogram the DAI link DMA to ensure
it is in sync with the host PCM DMA.

Use same state tracking logic to handle both restart and
system resume flows. Use link_prepared field of
'struct hdac_ext_stream' to store the state, instead of
adding redundant fields to SOF specific structs.
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190722141402.7194-18-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>