scsi: ufs: host: mediatek: Add DDR_EN setting

On MT6989 and later platforms, control of DDR_EN has been switched from
SPM to EMI. To prevent abnormal access to DRAM, it is necessary to wait
for 'ddren_ack' or assert 'ddren_urgent' after sending 'ddren_req'.

Introduce the DDR_EN configuration in the UFS initialization flow,
utilizing the assertion of 'ddren_urgent' to maintain performance.

Signed-off-by: Naomi Chu <naomi.chu@mediatek.com>
Link: https://lore.kernel.org/r/20250722030841.1998783-3-peter.wang@mediatek.com


Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Reviewed-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>