hal: add support for msmcobalt

Add initial audio support for MSMCOBALT target

Change-Id: I06cd6a558d8622c7b8ff82b5531478adea96e631
diff --git a/hal/msm8974/platform.h b/hal/msm8974/platform.h
index 4f2bb3d..be5160a 100644
--- a/hal/msm8974/platform.h
+++ b/hal/msm8974/platform.h
@@ -360,6 +360,8 @@
 #define FM_RX_VOLUME "PRI MI2S LOOPBACK Volume"
 #elif PLATFORM_MSM8996
 #define FM_RX_VOLUME "Tert MI2S LOOPBACK Volume"
+#elif PLATFORM_MSMCOBALT
+#define FM_RX_VOLUME "SLIMBUS_8 LOOPBACK Volume"
 #else
 #define FM_RX_VOLUME "Internal FM RX Volume"
 #endif