powerpc/85xx: Enable display support for t1042rdb

Add a diu_ops implementation for t1042rdb.

Signed-off-by: Jason Jin <jason.jin@nxp.com>
[Meng Yi: Made file t1042rdb-specific]
Signed-off-by: Meng Yi <meng.yi@nxp.com>
[scottwood: clean up commit message]
Signed-off-by: Scott Wood <oss@buserror.net>