Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/nvdimm/../../tools/testing/nvdimm/test/iomap.o
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://patch.msgid.link/r/20240526-md-testing-nvdimm-v1-1-f8b617bb28e1@quicinc.comSigned-off-by: Ira Weiny <ira.weiny@intel.com>