ndtest: Add dimms to the two buses

A config array is used to hold the dimms for each bus. These dimms are
registered with nvdimm, and new nvdimms are created on the buses.

Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Link: https://lore.kernel.org/r/20201222042240.2983755-4-santosh@fossix.org


Signed-off-by: Dan Williams <dan.j.williams@intel.com>