ARM: ux500: add PRCM register base for pinctrl

This adds the PRCM register range base as a resource to
the pinctrl driver do we can break the dependency to the
PRCMU driver and handle these registers in the driver
alone.

Cc: arm@kernel.org
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>