spi: dt-bindings: qcom,spi-qcom-qspi: Add iommus

Add iommus binding for DMA mode support

Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/1682328761-17517-2-git-send-email-quic_vnivarth@quicinc.com


Signed-off-by: Mark Brown <broonie@kernel.org>