regulator: Add support for twl6030 regulators

This patch updates the regulator driver to add support
for TWL6030 PMIC specific LDO regulators.
SMPS resources are not yet supported for TWL6030 and
also .set_mode and .get_status for LDO's are yet to
be implemented for TWL6030.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Balaji T K <balajitk@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>