scsi: ufs: ufs-mediatek: gate ref-clk during Auto-Hibern8

scsi: ufs: ufs-mediatek: gate ref-clk during Auto-Hibern8

In current UFS driver design, hba->uic_link_state will not be changed after
link enters Hibern8 state by Auto-Hibern8 mechanism.  In this case,
reference clock gating will be skipped unless special handling is
implemented in vendor's callbacks.

Support reference clock gating during Auto-Hibern8 period in MediaTek
Chipsets: If link state is already in Hibern8 while Auto-Hibern8 feature is
enabled, gate reference clock in setup_clocks callback.

Link: https://lore.kernel.org/r/20200129105251.12466-5-stanley.chu@mediatek.com
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>