phy: samsung: ufs: constify samsung_ufs_phy_cfg

Put const qualifier of samsung_ufs_phy_cfg pointer because they will
not be changed from drvdata.

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220607072907.127000-4-chanho61.park@samsung.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>