drm/msm/dsi: make save_state/restore_state callbacks accept msm_dsi_phy

Make save_state/restore callbacks accept struct msm_dsi_phy rather than
struct msm_dsi_pll. This moves them to struct msm_dsi_phy_ops, allowing
us to drop struct msm_dsi_pll_ops.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Stephen Boyd <swboyd@chromium.org> # on sc7180 lazor
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Link: https://lore.kernel.org/r/20210331105735.3690009-18-dmitry.baryshkov@linaro.org
Signed-off-by: Rob Clark <robdclark@chromium.org>