scsi: ufs: remove a redundant field from hba struct

Remove a redundant field, namely complete_time_stamp, from the hba struct.
Meanwhile, fix the logic due to the removal of it.

Change-Id: I83771d5b0a836d60f8b08601035f4368373b2e06
Signed-off-by: Can Guo <cang@codeaurora.org>