mach-ux500: basic HREFv60 support v2

The HREFv60 variant of the MOP500 family of boards remove the
external GPIO expander and route these pins back to some of the
readily available internal GPIO pins instead.

Based on a patch by Bibek Basu <bibek.basu@stericsson.com> for
an internal kernel version.

Cc: Bibek Basu <bibek.basu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>