removing addr_needs_map in struct dma_mapping_ops

[FUJITA Tomonori]

I'm trying to convert POWERPC to use asm-generic/dma-mapping-common.h.

POWERPC needs addr_needs_map() in struct dma_mapping_ops for SWIOTLB
support but I want to avoid add addr_needs_map() in struct
dma_map_ops. IIRC, you guys think it as a temporary solution and
talked about defining something like struct dma_data. Then we could

struct dev_archdata {
       ...

       struct dma_data *ddata;
};

or

struct dev_archdata {
       ...

       struct dma_data ddata;
};


struct dma_data needs dma_direct_offset, iommu_table, dma_base, and
dma_window_size, anything else?


Is it acceptable?