common/sfc_efx/base: support NIC DMA memory regions API

common/sfc_efx/base: support NIC DMA memory regions API

NIC DMA memory regions API allows to establish mapping of DMA addresses
used by NIC to host IOVA understood by the host when IOMMU is absent
and NIC cannot address entire host IOVA space because of too small
DMA mask.

The API does not allow to address entire host IOVA space, but allows
arbitrary regions of the space really used for the NIC DMA.

A DMA region needs to be mapped in order to perform MCDI initialization.
Since the NIC has not been probed at that point, its configuration cannot
be accessed and there an UNKNOWN mapping type is assumed.

Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>