use generic DMA mapping code in powerpc V4

[Christian Zigotzky]

Hi Christoph,

Thanks a lot for your reply. I will test your patches tomorrow.

Cheers,
Christian

Sent from my iPhone

> On 12. Dec 2018, at 15:15, Christoph Hellwig <hch at lst.de> wrote:
> 
> Thanks for bisecting.  I've spent some time going over the conversion
> but can't really pinpoint it.  I have three little patches that switch
> parts of the code to the generic version.  This is on top of the
> last good commmit (977706f9755d2d697aa6f45b4f9f0e07516efeda).
> 
> Can you check with whіch one things stop working?
> 
> 
> <0001-get_required_mask.patch>
> <0002-swiotlb-dma_supported.patch>
> <0003-nommu-dma_supported.patch>
> <0004-alloc-free.patch>