scsi: qla2xxx: Use dma_pool_zalloc()

Use dma_pool_zalloc() instead of dma_pool_alloc() and memset().

Link: https://lore.kernel.org/r/1615603275-14303-1-git-send-email-wangqing@vivo.com


Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Wang Qing <wangqing@vivo.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>