ASoC: Intel: Skylake: Fix resource cleanup on teardown

ASoC: Intel: Skylake: Fix resource cleanup on teardown

MCPS free was being done from PGA context which will free up MCPS
for only last modules in a pipe and not the rest causing MCPS
leak and eventual audio loss due to no "free" MCPS.

This needs to be freed for every module while cleaning up the
modules, so move the check to
skl_tplg_mixer_dapm_post_pmd_event()

Signed-off-by: Mohan Krishna Velaga <mohan.krishnax.velaga@intel.com>
Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>