regulator: ab8500: delete non-devicetree probe path

The Ux500 platform has been converted to do device-tree only
boots, no longer supports platform data passing, so this
probe path is unused. Delete it, simplifying the driver a
whole lot.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>