Fixes coccicheck warning:

./drivers/scsi/dpt_i2o.c:3070:11-29: WARNING:
 dma_alloc_coherent use in sys_tbl already zeroes out memory, so memset is not needed
./drivers/scsi/dpt_i2o.c:2780:10-28: WARNING:
 dma_alloc_coherent use in status already zeroes out memory, so memset is not needed
./drivers/scsi/dpt_i2o.c:2834:20-38: WARNING:
 dma_alloc_coherent use in pHba -> reply_pool already zeroes out memory, so memset is not needed
./drivers/scsi/dpt_i2o.c:1328:10-28: WARNING:
 dma_alloc_coherent use in status already zeroes out memory, so memset is not needed

Link: https://lore.kernel.org/r/20200718123224.1202-1-wanghai38@huawei.comReported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>