[FEATURE][Zephyr] Implement arch_cpu_disable_core and cpu_power_down_core in wrapper.c

[kv2019i]

Is your feature request related to a problem? Please describe.
Currently secondary cores are only powered down when DSP is put to suspend, or via out-of-band means (on Intel cAVS1.5, host controls power directly for the DSP cores).

Zephyr now implements interface to start/stop xtensa cores, so this should be used in wrapper.c.

[lgirdwood]

We need to start using native Zephyr APIs and wrap the xtos version of these functions.

[bkokoszx]

@mwasko fyi

[kv2019i]

Implemented with #5298 .

The native interface will be a Zephyr replacement of SOF runtime PM for DSP cores.

[lgirdwood]

@kv2019i can we close now ?

[kv2019i]

Yes, closing.

[kv2019i]

Unfortunately have to reopen this immediately back :( -> #5303

[kv2019i]

With @juimonen 's PR #7183 merged, we can close this.