regulator: Add pf8x00 regulator bindings

Add NXP PF8100/PF8121A/PF8200 regulators bindings.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Link: https://lore.kernel.org/r/20201130112329.104614-1-jagan@amarulasolutions.com


Signed-off-by: Mark Brown <broonie@kernel.org>