DSP core management refinement series

[keyonjie]

This is aim to address issue #2824

This basically comes from the old PR #888.

It enable the widget/component-level multi-core support via below changes:

1. add ref counts for each DSP cores.
2. add cores_status_mutex to protect core status.
3. update ref counts of cores and enabled_core_mask at probe, suspend, and FW booted to proper values.
4. add helpers snd_sof_dsp_core_get/put as the unified DSP cores access at runtime, which will manage the ref counts and enabled_core_mask internally.
5. switch to use the unified interface at _widget_setup() and _widget_free() for DSP cores power control.
6. with the above implemented, a bonus is that we can support decent pipelines tearing down on suspending now.

This is verified on TGL platform with DSM run on the Core 1 and others on Core 0.