block: t10-pi: add MODULE_DESCRIPTION()

Fix the allmodconfig 'make W=1' issue:

WARNING: modpost: missing MODULE_DESCRIPTION() in block/t10-pi.o

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240516-md-t10-pi-v1-1-44a3469374aa@quicinc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>