scsi: ufs-mediatek: Assign arguments with correct type

In ufs_mtk_unipro_set_lpm(), use specific unsigned values as the argument
to invoke ufshcd_dme_set().

At the same time, change the name of ufs_mtk_unipro_set_pm() to
ufs_mtk_unipro_set_lpm() to align the naming convention in MediaTek UFS
driver.

Link: https://lore.kernel.org/r/20201029115750.24391-2-stanley.chu@mediatek.com


Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>