hal: Add support for Native Audio(44.1kHz)

- Changes for device/Usecase selection
- Add new and combo devices for headphones
- Combo device handling
- Add new backend and logic to handle multiple
  backends
- Remove hardcoded mixers and select them
  dynamically based on the device

Change-Id: I7207291f2c27da13ba0cc77c66de1144f4b9888a
diff --git a/hal/audio_extn/utils.c b/hal/audio_extn/utils.c
index 82b596f..dbfac87 100644
--- a/hal/audio_extn/utils.c
+++ b/hal/audio_extn/utils.c
@@ -430,6 +430,7 @@
      * than all sample rates in list for the input bit width.
      */
     sample_rate = CODEC_BACKEND_DEFAULT_SAMPLE_RATE;
+
     list_for_each(node_i, &so_info->sample_rate_list) {
         ss_info = node_to_item(node_i, struct stream_sample_rate, list);
         if ((sample_rate <= ss_info->sample_rate) &&
@@ -437,7 +438,7 @@
             app_type_cfg->app_type = so_info->app_type_cfg.app_type;
             app_type_cfg->sample_rate = sample_rate;
             app_type_cfg->bit_width = so_info->app_type_cfg.bit_width;
-            ALOGV("%s Assuming default sample rate. app_type_cfg->app_type %d, app_type_cfg->sample_rate %d, app_type_cfg->bit_width %d",
+            ALOGV("%s Assuming sample rate. app_type_cfg->app_type %d, app_type_cfg->sample_rate %d, app_type_cfg->bit_width %d",
                    __func__, app_type_cfg->app_type, app_type_cfg->sample_rate, app_type_cfg->bit_width);
             return true;
         }