scsi: message: fusion: Declare SCSI host template members const

Make it explicit that the SCSI host templates are not modified.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230322195515.1267197-8-bvanassche@acm.org


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>