lenovo/legion/16irx8h: fix audio for Realtek ALC287 codec

Add kernel parameter 'snd_hda_intel.enable_msi=1' to enable proper
audio functionality for internal speakers on Lenovo Legion Pro 7 16IRX8H
laptops with Realtek ALC287 audio codec.

Without this fix, the speakers remain silent despite PipeWire/PulseAudio
showing audio playback as working correctly. The MSI (Message Signaled
Interrupts) parameter resolves the audio output issue.

Hardware tested:
- Lenovo Legion Pro 7 16IRX8H (model 82WQ)
- Realtek ALC287 audio codec (subsystem ID 0x17aa3886)

Author: i-am-logger

lenovo/legion/16irx8h/default.nix

@@ -34,6 +34,12 @@
   # Cooling management
   services.thermald.enable = lib.mkDefault true;
 
+  # Audio fix for Realtek ALC287 codec
+  # Enables proper audio functionality for internal speakers
+  boot.kernelParams = [
+    "snd_hda_intel.enable_msi=1"
+  ];
+
   # √(2560² + 1600²) px / 16 in ≃ 189 dpi
   services.xserver.dpi = 189;
 }