regulators: Moved define for number of regulators in ab8500

The define for number of regulators is moved from ab8500-core to
ab8500-regulator so that the regulator driver can be updated
independently of ab8500-core. This also changes the platform
configuration structure of ab8500-core so that it contains a
pointer to the regulator_init_data array plus number of
regulators instead of an fixed size array of pointers to
regulator_init_data.

Signed-off-by: Bengt Jonsson <bengt.g.jonsson@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>