scsi: ufs: core: Add reinit_notify() callback

reinit_notify() callback can be used by the UFS controller drivers to
perform changes required for UFSHCD reinit that can happen during max gear
switch.

Tested-by: Andrew Halaney <ahalaney@redhat.com> # Qdrive3/sa8540p-ride
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>