fix Surface positions are not floats

Added Surface.setPosition(float, float) which allows to set a surface's
position in float.

Bug: 5239859
Change-Id: I903aef4ad5b5999142202fb8ea30fe216d805711
diff --git a/include/private/surfaceflinger/LayerState.h b/include/private/surfaceflinger/LayerState.h
index d2fed41..3eb5c99 100644
--- a/include/private/surfaceflinger/LayerState.h
+++ b/include/private/surfaceflinger/LayerState.h
@@ -54,8 +54,8 @@
             };
             SurfaceID       surface;
             uint32_t        what;
-            int32_t         x;
-            int32_t         y;
+            float           x;
+            float           y;
             uint32_t        z;
             uint32_t        w;
             uint32_t        h;