mx5: Select CONFIG_REVISION_TAG
FSL 2.6.35 kernel expects that revision tag is passed by the bootloader.
Select CONFIG_REVISION_TAG so that mx53 boards can work properly with 2.6.35.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>