scsi: ufs: Fix up auto hibern8 enablement

scsi: ufs: Fix up auto hibern8 enablement

[ Upstream commit 71d848b8d97ec0f8e993d63cf9de6ac8b3f7c43d ]

Fix up possible unclocked register access to auto hibern8 register in
resume path and through sysfs entry. Meanwhile, enable auto hibern8 only
after device is fully initialized in probe path.

Link: https://lore.kernel.org/r/1573798172-20534-4-git-send-email-cang@codeaurora.org
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>