twl-regulator: Define critical regulators as always_on

Defines VIO, VDD1, VDD2, VPLL1 and VINT* regulators as always_on by default
since they are critical to TWL and its master's functionality and should
be on in all cases where RegFW is used

Signed-off-by: Juha Keski-Saari <ext-juha.1.keski-saari@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>