scsi: Avoid sign extension of scsi_device.type

This patch avoids that smatch reports the following:

drivers/scsi/scsi_sysfs.c:506 scsi_bus_uevent() warn: argument 3 to %02x specifier has type 'char'
drivers/scsi/scsi_sysfs.c:872 sdev_show_modalias() warn: argument 4 to %02x specifier has type 'char'

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>