Small fix to VideoMixer

[Tim-Philipp Müller]

On Fri, 2012-08-24 at 13:38 -0400, Michael Rubinstein wrote:

> " LITTLE_ENDIAN" without the "G_" in not defined,  so the test comes
> out wrong. 

Thanks, I've pushed your fix now. It would be great if next time you
could file a bug in bugzilla [0] instead to make sure the problem or
patch isn't overlooked or forgotten about.

 Cheers
  -Tim

[0] http://gstreamer.freedesktop.org/bugs/