scsi: hpsa: Fix pointer dereferenced before checking

The dev->raid_map is dereferencing before null checking, so move
 it after checking.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>

drivers/scsi/hpsa.c

@@ -5104,7 +5104,7 @@ static int hpsa_scsi_ioaccel_raid_map(struct ctlr_info *h,
 {
 	struct scsi_cmnd *cmd = c->scsi_cmd;
 	struct hpsa_scsi_dev_t *dev = cmd->device->hostdata;
-	struct raid_map_data *map = &dev->raid_map;
+	struct raid_map_data *map;
 	struct raid_map_disk_data *dd = &map->data[0];
 	int is_write = 0;
 	u32 map_index;
@@ -5137,6 +5137,8 @@ static int hpsa_scsi_ioaccel_raid_map(struct ctlr_info *h,
 	if (!dev)
 		return -1;
 
+	map = &dev->raid_map;
+
 	if (dev->in_reset)
 		return -1;