scsi: core: Fix a comment in function scsi_host_dev_release()

scsi: core: Fix a comment in function scsi_host_dev_release()

[ Upstream commit 7a21f85b3dca8b596b5f8ca1b31f3066f851a80b ]

Commit 4b9fa72cf737 ("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.com
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stable-dep-of: be03df3d4bfe ("scsi: core: Fix a procfs host directory removal regression")
Signed-off-by: Sasha Levin <sashal@kernel.org>