arm64: dts: broadcom: align SMMU node names with DT schema

DT schema expects certain pattern for IOMMU/SMMU nodes:

  northstar2/ns2-svk.dtb: mmu@64000000: $nodename:0: 'mmu@64000000' does not match '^iommu@[0-9a-f]*'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Ray Jui <ray.jui@broadcom.com>
Link: https://lore.kernel.org/r/20221222092456.79203-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>