Olof Johansson [off-list ref] writes:

It's a known issue due to dependencies with a driver tree. :(

Robert, this is unfortunate. What's the dependent patches? We can pick
them up in our tree as duplicates if needed.

I'd rather postpone one of the patches, as I explained in the pull request.
As Stephen noticed, this will be :
0d0b16b8e008 ("dmaengine: pxa: make the filter function internal")

I'll queue this one for the 4.20 cycle. By the way, all of this cames from the
fact that I didn't take this very patch in my imutable branch for this change
...

I'll also resend a pull request, without this patch if that's good for you,
which will solve the breakage.

Cheers.

-- 
Robert