dt-bindings: display: st,stm32-ltdc: add access-controllers property

dt-bindings: display: st,stm32-ltdc: add access-controllers property

access-controllers is an optional property that allows a peripheral to
refer to one or more domain access controller(s).

This property is added when the peripheral is under the STM32 firewall
controller.  It allows an accurate representation of the hardware, where
the peripheral is connected to a firewall bus.  The firewall can then check
the peripheral accesses before allowing its device to probe.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Yannick Fertre <yannick.fertre@foss.st.com>
Link: https://lore.kernel.org/r/20250822-drm-misc-next-v5-2-9c825e28f733@foss.st.com
Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>