Comment 14 for bug 1915117

Based on https://bugzilla.kernel.org/show_bug.cgi?id=201251#c164, I generated the skl_hda_dsp_generic-tplg.bin and put it under /lib/firmware for the Intel SST driver. With my own build kernel (SOF and Intel SST all enabled), the dmesg shows that the ALC256 been found as down below.
```
[ 26.615808] snd_soc_skl 0000:00:1f.3: Direct firmware load for 9d71-ACRSYS-ACRPRDCT-2-tplg.bin failed with error -2
[ 26.615813] snd_soc_skl 0000:00:1f.3: tplg fw 9d71-ACRSYS-ACRPRDCT-2-tplg.bin load failed with -2, trying alternative tplg name skl_hda_dsp_generic-tplg.bin
[ 26.630399] snd_soc_skl 0000:00:1f.3: ASoC: Parent card not yet available, widget card binding deferred
[ 26.687728] debugfs: File 'DMIC01 Rx' in directory 'dapm' already present!
[ 26.687997] HDMI HDA Codec ehdaudio0D2: hdac_hdmi_present_sense: disconnect for pin:port 5:0
[ 26.688224] HDMI HDA Codec ehdaudio0D2: hdac_hdmi_present_sense: disconnect for pin:port 6:0
[ 26.688434] HDMI HDA Codec ehdaudio0D2: hdac_hdmi_present_sense: disconnect for pin:port 7:0
[ 26.696721] snd_hda_codec_realtek ehdaudio0D0: autoconfig for ALC256: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
[ 26.696724] snd_hda_codec_realtek ehdaudio0D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
[ 26.696726] snd_hda_codec_realtek ehdaudio0D0: hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
[ 26.696727] snd_hda_codec_realtek ehdaudio0D0: mono: mono_out=0x0
[ 26.696728] snd_hda_codec_realtek ehdaudio0D0: inputs:
[ 26.696729] snd_hda_codec_realtek ehdaudio0D0: Internal Mic=0x1a
[ 26.696730] snd_hda_codec_realtek ehdaudio0D0: Headset Mic=0x19
```
Now the `aplay -l` and `arecord -l` can show audio interfaces as expected. However, the `pactl list sinks`and `pactl list sources` still gives `Dummy` devices. Thus the Sound Settings display still show `Dummy Output`. We may need to update the pulseausio for this.