scsi: ufs: fix the AH8 timer manipulation sysfs entry

Manipulating the new AH8 timer sysfs entry introduced by upstream merge can
lead to possible unclocked register access error because it does not take
SW clock gating into consideration. Fix it by holding clock before access
to AH8 timer. Meanwhile, migrate the old AH8 timer manipulation sysfs entry
to the new one and change the AH8 timer timeout from 150ms back to 1ms.

Change-Id: If488522f3d9297d3d441c9bfc2f0029d45584f8c
Signed-off-by: Can Guo <cang@codeaurora.org>