Using 2048 byte buffer and onle 128 bytes is needed.

Create nee LFPC_NVMET_DATA_BUF_SIZE define to use for NVMET RQ/MRQs.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>