scsi: target: core: pr: Initialize arrays at declaration time

Avoids calling memset().

Link: https://lore.kernel.org/r/20210228055645.22253-21-chaitanya.kulkarni@wdc.com
Link: https://lore.kernel.org/r/20210228055645.22253-22-chaitanya.kulkarni@wdc.com
Link: https://lore.kernel.org/r/20210228055645.22253-23-chaitanya.kulkarni@wdc.com


Reviewed-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>