tools/testing/nvdimm, acpica: fix flag rename build breakage

Commit ca321d1c "ACPICA: Update NFIT table to rename a flags field"
performed a tree-wide s/ACPI_NFIT_MEM_ARMED/ACPI_NFIT_MEM_NOT_ARMED/
operation, but missed the tools/testing/nvdimm/ directory.

Cc: Bob Moore <robert.moore@intel.com>
Cc: Lv Zheng <lv.zheng@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>