hal: add support for hfp on auto platform

Add auto platform specific pcm device id and
playback volume control to support hfp with
dual asm loopback.

Change-Id: I6bd2ae63c8733dd770f48c1b2557c4d3d5a6b101
diff --git a/hal/msm8974/platform.h b/hal/msm8974/platform.h
index 74ce72f..eb6edb0 100644
--- a/hal/msm8974/platform.h
+++ b/hal/msm8974/platform.h
@@ -495,6 +495,9 @@
 #elif PLATFORM_BEAR_FAMILY
 #define HFP_SCO_RX 17
 #define HFP_ASM_RX_TX 18
+#elif PLATFORM_AUTO
+#define HFP_SCO_RX 36
+#define HFP_ASM_RX_TX 29
 #else
 #define HFP_SCO_RX 23
 #define HFP_ASM_RX_TX 24