regulator: dt-bindings: Add PMX55 compatibles

Add PMX55 compatibles for PMIC found in SDX55 platform

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20201126093018.1085594-1-vkoul@kernel.org


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