Add pm runtime support and move clock handling there.
Close the clocks at suspend to reduce the power consumption.

fsl_esai_suspend is replaced by pm_runtime_force_suspend.
fsl_esai_resume is replaced by pm_runtime_force_resume.
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>