dt-bindings: memory-controllers: samsung,exynos4210-srom: Split out child node properties

dt-bindings: memory-controllers: samsung,exynos4210-srom: Split out child node properties

In order to validate devices in child nodes, the device schemas need to
reference any child node properties. In order to do that, the properties
for child nodes need to be included in mc-peripheral-props.yaml.

"reg: { maxItems: 1 }" was also incorrect. It's up to the device schemas
how many reg entries they have.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250203-dt-lan9115-fix-v1-3-eb35389a7365@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>