mfd: Add manual ab8500-gpadc batt temp activation for AB8500 3.0

mfd: Add manual ab8500-gpadc batt temp activation for AB8500 3.0

In AB8500 3.0 the pull-up supplying the NTC must be manually activated.
Add enumerators to chip version detection logic.

Signed-off-by: Kalle Komierowski <karl.komierowski@stericsson.com>
Reviewed-by: Johan Palsson <johan.palsson@stericsson.com>
Reviewed-by: Daniel Willerud <daniel.willerud@stericsson.com>
Reviewed-by: Jonas Aberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>