scsi: ufs: core: Pass the clock scaling timeout as an argument

Prepare for adding an additional ufshcd_clock_scaling_prepare() call with a
different timeout.

Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>