ANDROID: scsi: ufs: Adjust ufshcd_uic_hibern8_*() declarations

Move the ufshcd_uic_hibern8_enter() and ufshcd_uic_hibern8_exit()
declarations to where these occur in the upstream code.

Bug: 204438323
Change-Id: Ia7fbee3828baefe53e11f7189522abe129479f43
Signed-off-by: Bart Van Assche <bvanassche@google.com>