wfd-csys: Enable Android.mk 64-bit compilation

Change-Id: Ic26502e5f59499ea8f2902f8258f70013e7364a8
diff --git a/libaac/Android.mk b/libaac/Android.mk
index ec4afc6..96a7fe2 100644
--- a/libaac/Android.mk
+++ b/libaac/Android.mk
@@ -21,7 +21,7 @@
 
 LOCAL_VENDOR_MODULE := true
 
-LOCAL_32_BIT_ONLY := true
+LOCAL_MULTILIB := 64
 LOCAL_MODULE := libwfdaac_vendor
 LOCAL_CFLAGS += -O0