regulator: tps65217: Add tps65217 regulator driver

This patch adds tps65217 PMIC as a regulator

The regulator module consists of 3 DCDCs and 4 LDOs. The output
voltages are configurable and are meant to supply power to the
main processor and other components

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>