dt-bindings: mfd: fsl,mc13xxx: Convert txt to DT schema

Convert the txt mc13xxx bindings to DT schema attempting to keep most
information. The nodes codec and touchscreen are not part of the new
schema since it was only briefly mentioned before.
Following the convention, rename led-control to fsl,led-control.

Signed-off-by: Alexander Kurz <akurz@blala.de>
Reviewed-by: "Rob Herring (Arm)" <robh@kernel.org>
Link: https://lore.kernel.org/r/20250829201517.15374-6-akurz@blala.de


Signed-off-by: Lee Jones <lee@kernel.org>