soc/qbman: Move dma-mapping.h include to qman_priv.h

With the include there it fixes all build failures in this
directory caused by commit 461a6946.

Fixes: 461a6946

 ("iommu: Remove pci.h include from trace/events/iommu.h")
Signed-off-by: Joerg Roedel <jroedel@suse.de>