Remove Xrun recovery inside FW.

[keyonjie]

SOF FW will need to remove recovery trying code, e.g. pipeline_prepare(), trigger start, and schedule copy.

Just keep sending Xrun IPC to host driver side, host framework(e.g. ALSA) will help to handle this recovery if possible, e.g. trigger stop and start.

[lgirdwood]

ok, no objections from me but we need to make sure drivers does do the recovery.

[keyonjie]

@lgirdwood sure, @bardliao is working on that.

[bardliao]

@keyonjie @lgirdwood My plan is to return SNDRV_PCM_POS_XRUN in sof_pcm_pointer when kernel receive the XRUN message from FW.

[lgirdwood]

@mmaka1 any comment on your preference here about who recovers XRUN ?

[slawblauciak]

FW xrun recovery will be disabled once driver fully handles the situation
thesofproject/linux#660

[jajanusz]

WIP #1439

[tlauda]

It's disabled in FW.