move vector math out of libui

created a new header-only static libmath lib

Test: built & ran
Bug: n/a
Change-Id: Ic63ef5f54d9a0de07a9ab9e4d67be01ab6169fc0
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index f52bd2d..c43786a 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -40,7 +40,7 @@
 
 #include <ui/FenceTime.h>
 #include <ui/PixelFormat.h>
-#include <ui/mat4.h>
+#include <math/mat4.h>
 
 #include <gui/FrameTimestamps.h>
 #include <gui/ISurfaceComposer.h>