audio-lnx: ANDROID_BUILD_TOP is deprecated.

ANDROID_BUILD_TOP variable is deprecated and thus all paths are
assumed to be relative to the top directory.

Change-Id: Ifc1bba67bf47092a37336581990d4bcce82a72f5
diff --git a/ipc/Android.mk b/ipc/Android.mk
index fe9ce0f..942a186 100644
--- a/ipc/Android.mk
+++ b/ipc/Android.mk
@@ -29,7 +29,7 @@
 ifneq ($(findstring vendor,$(LOCAL_PATH)),)
 
 ifneq ($(findstring opensource,$(LOCAL_PATH)),)
-	AUDIO_BLD_DIR := $(ANDROID_BUILD_TOP)/vendor/qcom/opensource/audio-kernel
+	AUDIO_BLD_DIR := $(shell pwd)/vendor/qcom/opensource/audio-kernel
 endif # opensource
 
 DLKM_DIR := $(TOP)/device/qcom/common/dlkm