ARM: ux500: Add regulator platform data for AB8500 external regulators

Pass constraint information for recently supported external AB8500
controlled regulators. Also change the start-up initialisation settings
for each of the 3 supported external supplies to low-power, off and
high-power for supply 1, 2 and 3 respectively.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>