scsi: Use g_new() & friends where that makes obvious sense

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi/lsi53c895a.c

@@ -781,7 +781,7 @@ static void lsi_do_command(LSIState *s)
     }
 
     assert(s->current == NULL);
-    s->current = g_malloc0(sizeof(lsi_request));
+    s->current = g_new0(lsi_request, 1);
     s->current->tag = s->select_tag;
     s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun, buf,
                                    s->current);

hw/scsi/virtio-scsi.c

@@ -829,7 +829,7 @@ void virtio_scsi_common_realize(DeviceState *dev, Error **errp,
         virtio_cleanup(vdev);
         return;
     }
-    s->cmd_vqs = g_malloc0(s->conf.num_queues * sizeof(VirtQueue *));
+    s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues);
     s->sense_size = VIRTIO_SCSI_SENSE_SIZE;
     s->cdb_size = VIRTIO_SCSI_CDB_SIZE;