dt-bindings: arm: Remove obsolete RTSM DCSCB binding

The Arm VExpress DCSCB binding is unused and was only ever used on a s/w
model over 10 years ago. Remove it.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240510123238.3904779-2-robh@kernel.org


Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>