hal: add support to override volume gain to step mapping table

- if customer mapping is added in platform info file, use that
- in absence of customer table use default mapping

BUG 28897755
Change-Id: I4bf8bcf1913f16ad6298ff1f3fa5dd649c889b2a
diff --git a/post_proc/Android.mk b/post_proc/Android.mk
index 1a8550c..59ee105 100644
--- a/post_proc/Android.mk
+++ b/post_proc/Android.mk
@@ -53,6 +53,7 @@
 LOCAL_MODULE:= libvolumelistener
 
 LOCAL_C_INCLUDES := \
+        hardware/qcom/audio/hal \
 	$(call include-path-for, audio-effects)
 
 include $(BUILD_SHARED_LIBRARY)