regulator: twl: fix twl4030 support for smps regulators

SMPS regulator voltage control differs from the one of the LDO ones.
Current TWL code was using LDO regulator ops for controlling the SMPS
regulators, which fails. This was fixed fixed by adding separate
regulator type which uses correct logic and calculations for the
voltage levels.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org