fix[2228133] pixelflinger ignores the "vertical stride" leading to artifacts when playing back video

we lost the concept of vertical stride when moving video playback to EGLImage.
Here we bring it back in a somewhat hacky-way that will work only for the
softgl/mdp backend.
diff --git a/opengl/libagl/egl.cpp b/opengl/libagl/egl.cpp
index d04900e..80ddc02 100644
--- a/opengl/libagl/egl.cpp
+++ b/opengl/libagl/egl.cpp
@@ -651,7 +651,7 @@
         if (supportedCopybitsDestinationFormat(buffer.format)) {
             buffer_handle_t handle = this->buffer->handle;
             if (handle != NULL) {
-                gl->copybits.drawSurfaceBuffer = handle;
+                gl->copybits.drawSurfaceBuffer = this->buffer;
             }
         }
     }