scsi: ufs: renable AH8 timer on reset

Auto hibern8 timer will get reset as part of ufshcd_vops_full_reset(),
so reenable the timer in ufshcd_probe_hba().

Change-Id: I8ff85a9fd02f4a6b527666654728c4146cb61f5e
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[cang@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Can Guo <cang@codeaurora.org>