scsi: ufs: host: mediatek: Add clock scaling query function

Introduce a clock scaling readiness query function to streamline the
process of checking clock scaling parameters.  This function simplifies
the code by encapsulating the logic for determining if clock scaling is
ready.

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Link: https://lore.kernel.org/r/20250722030841.1998783-8-peter.wang@mediatek.com


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