ARM: ep93xx: tidy up TS-72xx Watchdog resources

The ts-72xx watchdog uses two byte sized registers. Tidy up the resource
declaration so that the proper information is shown in /proc/iomem.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>