qcom/audio/hal: Use linked list APIs from libcutils

- Replace the linked list implementation with relevant APIs
  available in libcutils

Bug: 8292602
Change-Id: I2db173b845cbf4f35e53738b272f7f4a79279f3b
diff --git a/hal/audio_hw.h b/hal/audio_hw.h
index 0781688..7a20a86 100644
--- a/hal/audio_hw.h
+++ b/hal/audio_hw.h
@@ -176,6 +176,7 @@
 
 // To store active use cases.
 struct audio_usecase {
+    struct listnode list;
     audio_usecase_t id;
     usecase_type_t  type;
     audio_devices_t devices;
@@ -215,7 +216,7 @@
     snd_device_t cur_in_snd_device;
     bool out_snd_device_active;
     bool in_snd_device_active;
-    struct audio_usecase usecase_list;
+    struct listnode usecase_list;
     struct audio_route *audio_route;
     int acdb_settings;