fix x86 swiotlb regression

Hi all, this patch fixes a regression in the x86 swiotlb conversion. This mostly happend because swiotlb_dma_support does the wrong thing (and did so for a long time) and we switched x86 to use it. There are a few others users of swiotlb_dma_supported that also look rather broken, but I'll take

fix x86 swiotlb regression

Hi all, this patch fixes a regression in the x86 swiotlb conversion. This mostly happend because swiotlb_dma_support does the wrong thing (and did so for a long time) and we switched x86 to use it. There are a few others users of swiotlb_dma_supported that also look rather broken, but I'll take