scsi: smartpqi: Convert snprintf() to scnprintf()

The entire Linux kernel has been slowly migrating from snprintf() to
scnprintf(), so we are doing our part. This article explains the rationale
for this change:

   https: //lwn.net/Articles/69419/

Link: https://lore.kernel.org/r/161549383357.25025.12363435617789964291.stgit@brunhilda


Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
Reviewed-by: Mike McGowen <mike.mcgowen@microchip.com>
Reviewed-by: Scott Teel <scott.teel@microchip.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Kevin Barnett <kevin.barnett@microchip.com>
Signed-off-by: Don Brace <don.brace@microchip.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>