Make tinyxml multilib both on the host.

CTS dependencies (audio quality) require a 64-bit tinyxml on the host.
Bug: 13751317

Change-Id: I3c8bf102830ee35473e4c1f5441d040f135201d2
diff --git a/Android.mk b/Android.mk
index fdc63db..f8c2b6c 100644
--- a/Android.mk
+++ b/Android.mk
@@ -24,7 +24,7 @@
 LOCAL_CFLAGS+= $(TOOL_CFLAGS)
 LOCAL_LDFLAGS:= $(TOOL_LDFLAGS) -lstdc++ -lc
 
-LOCAL_32_BIT_ONLY := true
+LOCAL_MULTILIB := both
 
 include $(BUILD_HOST_STATIC_LIBRARY)