ColdFire: uart: fix build failure for missing header files

The following commit introduces some build failures for ColdFire
platform.

commit abaef69f
Author: Marek Vasut <marex@denx.de>
Date:   Thu Sep 13 16:51:38 2012 +0200

Add the missed header files.

Sign-off-by: Alison Wang <b18965@freescale.com>