(TEMP) hwc: external: Enable default mirroring on hwc1.1

Related to bug: 7124159

UI Mirror works with tearing because sync operates at primary vsync.  Need
kernel patch to wait on external post.

Change-Id: I77116ef40ae25a2207feb5ca3cd9065ef0da6e4a
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/libhwcomposer/Android.mk b/libhwcomposer/Android.mk
index 4e52ede..8697b5a 100644
--- a/libhwcomposer/Android.mk
+++ b/libhwcomposer/Android.mk
@@ -16,5 +16,6 @@
                                  hwc_utils.cpp    \
                                  hwc_uevents.cpp  \
                                  hwc_mdpcomp.cpp  \
+                                 hwc_uimirror.cpp \
 
 include $(BUILD_SHARED_LIBRARY)