scsi: hisi_sas: Check whether debugfs is enabled before removing or releasing it

hisi_sas debugfs remove should be executed only when debugfs is enabled.
Check whether debugfs is enabled and then remove it only if enabled.

Signed-off-by: Yihang Li <liyihang9@huawei.com>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Link: https://lore.kernel.org/r/1705904747-62186-4-git-send-email-chenxiang66@hisilicon.com


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>