twl6030: regulator: Remove vsel tables and use formula for calculation

All twl6030 regulators can be programmed from 1.0v to 3.3v
with 100mV steps.
The below formula can be used to calculate the vsel values
to be programmed in the VREG_VOLTAGE registers.

Voltage(in mV) = 1000mv + 100mv * (vsel - 1)

Ex: if vsel = 0x9, mV = 1000 + 100 * (9 -1) = 1800mV.

This patch removes all existing VSEL tables for twl6030 adjustable
regulators and just uses the formula directly for vsel calculations
after verifing they fall in the allowed range.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>