ASoC: Intel: avs: DSP recovery and resume fixes

Merge series from Cezary Rojewski <cezary.rojewski@intel.com>:

Two fixes that are result of the recent discussions [1][2].

First adds missing locking around snd_pcm_stop() while the second fix
sets substream state to DISCONNECTED if any suspend/resume related
operation fails so that userspace has means to be aware that something
went wrong during said operation.