[refactor] remove va_args from DMAs

Now that only one type of request is allowed (layouts), remove va_args
for the DMA API, making it significantly cleaner.

Fix #49.
5 jobs for remove-dma-va-args in 9 minutes and 26 seconds
Status Job ID Name Coverage
  Style
passed #44601
integration
checkpatch

00:03:51

passed #44600
integration
repoquality

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  Build
passed #44602
make:generic

00:01:34

passed #44604
knl
make:knl

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passed #44603
make:out-of-tree

00:01:32