scsi: ufs: core: Add OPP support for scaling clocks and regulators

scsi: ufs: core: Add OPP support for scaling clocks and regulators

UFS core is only scaling the clocks during devfreq scaling and
initialization. But for an optimum power saving, regulators should also be
scaled along with the clocks.

So let's use the OPP framework which supports scaling clocks, regulators,
and performance state using OPP table defined in devicetree. For
accomodating the OPP support, the existing APIs (ufshcd_scale_clks,
ufshcd_is_devfreq_scaling_required and ufshcd_devfreq_scale) are modified
to accept "freq" as an argument which in turn used by the OPP helpers.

The OPP support is added along with the old freq-table based clock scaling
so that the existing platforms work as expected.

Co-developed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20231012172129.65172-3-manivannan.sadhasivam@linaro.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>