ASoC: fsl_asrc: Merge suspend/resume function to runtime_suspend/resume

With dedicated power domain for asrc, power can be disabled after
probe and pm runtime suspend, then the value of all registers need to
be restored in pm runtime resume. So we can merge suspend/resume function
to runtime_suspend/resume function and enable regcache only in end of
probe.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/1590141444-28668-1-git-send-email-shengjiu.wang@nxp.com


Signed-off-by: Mark Brown <broonie@kernel.org>