In current implementation, ab8500_regulator_info[0].regulator is not
unregistered if the error happen at i > 0.

This patch fixes the resource leak and also improves the readability.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Acked-by: NLinus Walleij <linus.walleij@stericsson.com>
Acked-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>