Fix commit 391dd8f1("scsi-bus: Refactor the code that retries requests"),
which split scsi_dma_restart_bh(), but the object_unref() belongs to
scsi_dma_restart_bh().
So, we should mv object_unref() from scsi_retry_requests() to
scsi_dma_restart_bh().
Signed-off-by: Yan Wang <wangyan122@huawei.com>
