Commit 3be8828f ("scsi: core: Avoid that ATA error handling can
trigger a kernel hang or oops") moved rcu to scsi_cmnd instead of
shost. Modify "shost->rcu" to "scmd->rcu" in a comment.

Link: https://lore.kernel.org/r/1620646526-193154-1-git-send-email-chenxiang66@hisilicon.comSigned-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>