Re: clean up the DMA mapping headers

I've pulled this into the dma-mapping for-next tree now.

clean up the DMA mapping headers

Hi all, this series cleans up the dma-mapping headers by moving everything not required by normal drivers out of into a new and then folding most other DMA mapping related headers either into the new dma-map-ops.h one, or by moving them to kernel/dma/ and thus out of the global scope. A bunch o