mfd: ab8500-core chip version cut 2.0 support

This patch adds support for chip version 2.0 or cut 2.0.
One new interrupt latch register - latch 12 - is introduced.

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