scsi: megaraid_sas: Use zeroing memory allocator than allocator/memset

Use pci_zalloc_consistent for allocating zeroed memory and remove
unnecessary memset function.

Done using Coccinelle.
Generated by: scripts/coccinelle/api/alloc/kzalloc-simple.cocci

Suggested-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Signed-off-by: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>