tools/testing/nvdimm: Align test resources to 128M

In preparation for libnvdimm growing new restrictions to detect section
conflicts between persistent memory regions, enable nfit_test to
allocate aligned resources. Use a gen_pool to allocate nfit_test's fake
resources in a separate address space from the virtual translation of
the same.

Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>