libeffects: move all libraries to vendor

Bug: 37490685
Test: equalizer works in google play music
Test: CleanSpec works
Change-Id: I9c1d19b5b5c5099edc9c20ff7728adc830ff4786
diff --git a/media/libeffects/preprocessing/Android.mk b/media/libeffects/preprocessing/Android.mk
index bd67aa1..bc03686 100644
--- a/media/libeffects/preprocessing/Android.mk
+++ b/media/libeffects/preprocessing/Android.mk
@@ -7,6 +7,7 @@
 LOCAL_MODULE_TAGS := optional
 LOCAL_MODULE_RELATIVE_PATH := soundfx
 
+LOCAL_VENDOR_MODULE := true
 LOCAL_SRC_FILES:= \
     PreProcessing.cpp