iommu 初始化失败

[FanFansfan]

[    0.365917] iommu: Default domain type: Translated 
[    0.365921] iommu: DMA domain TLB invalidation policy: strict mode 
[    3.495452] loongson-iommu 0000:00:1a.0: can't derive routing for PCI INT A
[    3.502372] loongson-iommu 0000:00:1a.0: PCI INT A: no GSI
[    3.507833] iommu membase (____ptrval____) pgtbase (____ptrval____) pgtsize 4000000 maxpages 1000

使用master分支，3A5000-7A2000_EVB prestable202308固件，测试iommu不可用。

[chenhuacai]

属于固件没有传递正确的中断信息吧。