MLK-17034-2: ASoC: fsl_sai: Move clock operation to pm runtime function

MLK-17034-2: ASoC: fsl_sai: Move clock operation to pm runtime function

In imx8 when systerm enter suspend state, the power of subsystem will be
off, the clock enable state will be lost after resume, but the runtime
resume function will be called after resume by pm, so need to move clock
enablement to runtime resume and clock disablement to runtime suspend.
Then after resume the clock enable state can be recovered.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>