scsi: ufs: enable auto hibern8 only after device initialization

Make sure auto hibern8 is enabled only after both host controller
and device initialization is complete. Enabling it before device
initialization could cause issues as the device might not be ready
to handle hibern8 enter/exit before initialization.

Change-Id: Ia3fb69dca00654dacd8d1faae34715e40e097480
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[cang@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Can Guo <cang@codeaurora.org>