ARM: ux500: Remove incorrect DB9540 PRCMU TCDM base location

The Tightly Coupled Data Memory for the DB9540 is actually in the
same place as the DB8500's. This definition is just plain wrong.

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