support range based offsets in dma-direct v2

Hi all,

this series adds range-based offsets to the dma-direct implementation.  The
guts of the change are a patch from Jim with some modifications from me,
but to do it nicely we need to ARM patches to prepare for it as well.

Changes since v1:
 - rebased on top of the latests dma-mapping for-next tree
 - add two more trivial ARM cleanups
 - remove the DMA property inheritance hack in usb
 - move the remaining copy of the ranges into the remoteproc driver
   as it should not be seen as a general API, but as a quirk for
   remoteproc that we need to fix ASAP

Diffstat: