[BUG] Topology2: sdw amp doesn't work with passthrough topology (invalid input num_pins: 0)

[bardliao]

Describe the bug
sdw amp doesn't work with PASSTHROUGH=true topologies.

To Reproduce
Add PASSTHROUGH=true in tplg-targets.cmake. Like

diff --git a/tools/topology/topology2/avs-tplg/tplg-targets.cmake b/tools/topology/topology2/avs-tplg/tplg-targets.cmake
index 5aeb446793ba..7a4dc85b9ac1 100644
--- a/tools/topology/topology2/avs-tplg/tplg-targets.cmake
+++ b/tools/topology/topology2/avs-tplg/tplg-targets.cmake
@@ -17,7 +17,7 @@ PREPROCESS_PLUGINS=nhlt,NHLT_BIN=nhlt-sof-hda-generic-4ch.bin,USE_CHAIN_DMA=true

 # IPC4 topology for TGL rt711 Headset + rt1316 Amplifier + rt714 DMIC
 "cavs-sdw\;sof-tgl-rt711-rt1316-rt714\;NUM_SDW_AMP_LINKS=2,SDW_DMIC=1,\
-PREPROCESS_PLUGINS=nhlt,NHLT_BIN=nhlt-sof-tgl-rt711-rt1316-rt714.bin"
+PREPROCESS_PLUGINS=nhlt,NHLT_BIN=nhlt-sof-tgl-rt711-rt1316-rt714.bin,PASSTHROUGH=true"

 "cavs-sdw\;sof-adl-rt711-l0-rt1316-l12-rt714-l3\;NUM_SDW_AMP_LINKS=2,SDW_DMIC=1"

Run aplay -Dhw:0,2 test.wav -vv

Reproduction Rate
100%

Expected behavior
aplay works without errors.

Impact
We can't test sdw amp with passthrough topologies.

Environment

1. Branch name and commit hash of the 2 repositories: sof (firmware/topology) and linux (kernel driver).
   • Kernel: {43f9252ea5a497a7952cb1efc9a94d10d28c6dae}
   • SOF: {8adbb85}
2. Name of the topology file
   • Topology: {sof-tgl-rt711-rt1316-rt714.tplg} and set PASSTHROUGH=true
3. Name of the platform(s) on which the bug is observed.
   • Platform: {TGL}

Screenshots or console output
aplay: set_params:1416: Unable to install hw params:

dmesg errors:

[  519.663985] sof-audio-pci-intel-tgl 0000:00:1f.3: widget alh-copier.SDW1-Playback.0 setup complete
[  519.663988] sof-audio-pci-intel-tgl 0000:00:1f.3: invalid input num_pins: 0 for queue allocation for alh-copier.SDW1-Playback.0
[  519.663991] sof-audio-pci-intel-tgl 0000:00:1f.3: failed to get queue ID for sink widget: alh-copier.SDW1-Playback.0