scsi: ufs: host: mediatek: Support UFS PHY runtime PM and correct sequence

Add support for UFS PHY runtime power management by probing the PHY
device and enabling its runtime PM. Ensure the correct sequence of
operations during suspend and resume: PHY suspend -> UFS suspend -> UFS
resume -> PHY resume.  Improve power management efficiency and system
stability with this enhancement.

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>