[SCSI] Deprecate SCSI_PROT_*_CONVERT operations

The checksum format is orthogonal to whether the protection information
is being passed on beyond the HBA or not.  It is perfectly valid to use
a non-T10 CRC with WRITE_STRIP and READ_INSERT.

Consequently it no longer makes sense to explicitly refer to the
conversion in the protection operation.  Update sd_dif and lpfc
accordingly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Ihab Hamadi <Ihab.Hamadi@Emulex.Com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>