scsi: storvsc: Payload buffer incorrectly sized for 32 bit kernels.

On a 32 bit kernel sizeof(void *) is not 64 bits as hv_mpb_array
requires. Also the buffer needs to be cleared or the upper bytes will
contain junk.
Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Cathy Avery <cavery@redhat.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/storvsc_drv.c

@@ -1495,9 +1495,9 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
 	if (sg_count) {
 		if (sg_count > MAX_PAGE_BUFFER_COUNT) {
 
-			payload_sz = (sg_count * sizeof(void *) +
+			payload_sz = (sg_count * sizeof(u64) +
 				      sizeof(struct vmbus_packet_mpb_array));
-			payload = kmalloc(payload_sz, GFP_ATOMIC);
+			payload = kzalloc(payload_sz, GFP_ATOMIC);
 			if (!payload)
 				return SCSI_MLQUEUE_DEVICE_BUSY;
 		}