The qman portals are platform devices themselves, so they should
handle dma mappings.  Creating a dummy platform device in order to
support dma mapping operations is not justified (and not portable).
Instead, do the mapping against the first portal that has been
initialised.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: NScott Wood <oss@buserror.net>