arm64: dts: hisilicon: normalize the node name of the SMMU devices

Change the node name of the SMMU devices to match "^iommu@[0-9a-f]*".
Otherwise, the errors similar to the following will be reported by
arm,smmu-v3.yaml.

smmu_pcie: $nodename:0: 'smmu_pcie' does not match '^iommu@[0-9a-f]*'

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>