dmesg check still influenced by DSP init fail

[xiulipan]

From https://sof-ci.01.org/linuxpr/PR1706/build2893/devicetest/ICL_RVP_HDA/check-runtime-pm-status.sh/check-runtime-pm-status.sh.txt

The DSP init fail in retry is still caught by our dmesg check by keyword "failed"

[xiulipan]

Fixed by #45