The previous driver did not support BUCK1-DVS3, BUCK1-DVS4, and
BUCK2-DVS2 modes. This patch adds such modes and an option to block
setting buck1/2 voltages out of the preset values.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>