ARM: ux500: Over-ride TCDM size when booting the DB8540 platform

The PRCMU's Tightly Coupled Data Memory on the DB8540 platform is
8kB larger than it's predecessor's. We need to reflect that in its
Device Tree. By re-specifying the address and size of the device
we effectively over-ride the previous values with more accurate
ones.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>