mfd: ab8500-core: Fix invalid free of devm_ allocated data

The objects allocated by devm_* APIs are managed by devres and are
freed when the device is detached. Hence there is no need to remove
them explicitly in remove function.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>