power: regulator: pfuze100: support non-independent mode

power: regulator: pfuze100: support non-independent mode

Some BUCKs could work in single/dual phase mode, not in independent
mode. In single/dual phase mode, registers of both regulators,
must be identically set. So configure mode and value for both BUCKs.

CONF registers are not touched, leave them as default OTP settings.

PFUZE100/200 SW3A/B, could work in single/dual phase mode, so introduce
a new macro by adding a pointer to the SW3B descriptor.

Signed-off-by: Peng Fan <peng.fan@nxp.com>