configs: msm8937: Add support for hfp pcm loopback id.

Added support for hfp pcd device id for loopback support
sdm429w_law BT4.2 use audio_platform_info_sdm429w.xml

Change-Id: If19365ec5a504a83bc58e79a73125a03284ba442
diff --git a/configs/msm8937/audio_platform_info_sdm429w.xml b/configs/msm8937/audio_platform_info_sdm429w.xml
index b582c6e..91a7a20 100644
--- a/configs/msm8937/audio_platform_info_sdm429w.xml
+++ b/configs/msm8937/audio_platform_info_sdm429w.xml
@@ -55,6 +55,7 @@
     <config_params>
         <param key="spkr_1_tz_name" value="wsa881x.0f"/>
         <param key="spkr_2_tz_name" value=""/>
+        <param key="hfp_pcm_dev_id" value="18"/>
     </config_params>
     <acdb_ids>
         <device name="SND_DEVICE_OUT_SPEAKER_PROTECTED" acdb_id="136"/>