scsi: ufs: Use ufshcd_config_pwr_mode() when scaling gear

scsi: ufs: Use ufshcd_config_pwr_mode() when scaling gear

When scaling gear, use ufshcd_config_pwr_mode() instead of
ufshcd_change_power_mode() so that vops_pwr_change_notify(PRE_CHANGE)
can be utilized to allow vendors use customized settings before
changing power mode.

Link: https://lore.kernel.org/r/1581485910-8307-2-git-send-email-cang@codeaurora.org
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>