dt-bindings: dma: Increase iommu maxItems for BAM DMA

Since SM8250 BAM DMA engine supports six iommu entries,
increase the maxItems in the iommu property section, without
which 'dtbs_check' would throw errors.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Link: https://lore.kernel.org/r/20230630082230.2264698-3-bhupesh.sharma@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>