mfd: Add regulator support for twl6040 VIO, V2V1 supplies

twl6040 has three power supply source:
VBAT needs to be connected to VBAT, VIO, and V2V1.
Add regulator support for the VIO, V2V1 supplies.
Initially handle the two supply together with bulk commands.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>