Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.
The error messages look like:
[ 3.008452] arm-smmu 5000000.iommu: Unhandled context fault:
fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8
[ 3.020123] arm-smmu 5000000.iommu: Unhandled context fault:
fsr=0x402, iova=0xf9800000, fsynr=0x3f0022, cbfrsynra=0x828, cb=8
This was tested on a custom board with a LS1028A SoC.