Whether the 'msi-map-mask' property is needed or not depends on how the
MSI interrupts are mapped and it should therefore not be described as
required.

Note that the current schema fails to detect omissions of the mask
property if the internal MSI controller properties are also present.

Link: https://lore.kernel.org/r/20240306095651.4551-3-johan+linaro@kernel.orgSigned-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>