scsi: ufs: Fix index of attributes query for WriteBooster feature

For WriteBooster feature related attributes, the index used by query shall
be LUN ID if LU Dedicated buffer mode is enabled.

Link: https://lore.kernel.org/r/20200522083212.4008-4-stanley.chu@mediatek.com


Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>