audio: remove obsolete lunchbox mixer XML

Change-Id: I7328bc52e7d32d44d083803cb5643606b8985d27
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 519863c..12faa39 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -51,3 +51,4 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/SHARED_LIBRARIES/libui_intermediates)
 $(call add-clean-step, rm -f $(PRODUCT_OUT)/root/default.prop)
 $(call add-clean-step, rm -f $(TARGET_OUT)/build.prop)
+$(call add-clean-step, rm -f $(PRODUCT_OUT)/system/etc/mixer_paths_lb.xml)