hal: spk_prot: fix initial calibration fail with usecase retry

Usecase id of PCM_CALIB_TX is overriden by AUDIO_RECORD
in audio_extn_spkr_prot_start_processing to reset calibration
to handset Mic.
audio_extn_spkr_prot_stop_processing API looks for usecase
PCM_CALIB_TX to delete the node from usecase list,
fails to find as usecase id is overriden and this node
remains in usecase list.
So when the initial calibration is happening, usecase list
empty check condition is failing and returns.
Avoid override usecase id to allow delete of list node
in stop_audio_processing API.

CRs-Fixed: 843262
Change-Id: I12c901efba39dad771d6df9c2332becd8ee9f1d8