For runtime suspend/resume, it is some different with suspend/resume,
e.g. codec power supply won't be switch off, codec jack detection
still working(to wake up system from Jack event), won't call call
snd_soc_suspend/resume, etc.

So here, we add a platform PM status, HSW_PM_STATE_RTD3, to make
the status more clear, when in idle, it will enter this status, to
transfer from HSW_PM_STATE_RTD3 to HSW_PM_STATE_D3, we will do those
extra jobs, and vice versa for resuming.
Signed-off-by: NJie Yang <yang.jie@intel.com>
Signed-off-by: NMark Brown <broonie@kernel.org>