hwc: Fix external display position calculation

YUV layer display positions are mapped to primary resolution
[e.g. 1920x1080] when MDP downscale is enabled, that needs to be
transformed to the original external resoltion [e.g. 1280x720].
This transformation is not taken care for 4kx2k YUV use case.

Change-Id: Ifa60773bf9fcd18676a3f05cd72a603beb165733
diff --git a/libhwcomposer/hwc_utils.cpp b/libhwcomposer/hwc_utils.cpp
index ce2da87..8d039ba 100644
--- a/libhwcomposer/hwc_utils.cpp
+++ b/libhwcomposer/hwc_utils.cpp
@@ -1831,6 +1831,10 @@
     Whf whf(getWidth(hnd), getHeight(hnd),
             getMdpFormat(hnd->format), hnd->size);
 
+    /* Calculate the external display position based on MDP downscale,
+       ActionSafe, and extorientation features. */
+    calcExtDisplayPosition(ctx, hnd, dpy, crop, dst, transform, orient);
+
     setMdpFlags(layer, mdpFlagsL, 0, transform);
     trimLayer(ctx, dpy, transform, crop, dst);