ARM: ux500: prcmu db8500 v2 support

This patch adds support for db8500 chip version 2.
The TCDM memory address of the PRCMU is changed and
dynamic detection of that is added.

Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>