drm/i915/dsc: stop using interim structure for calculated params

Stop using an interim structure rc_parameters for storing calculated
params and then setting drm_dsc_config using that structure. Instead put
calculated params into the struct drm_dsc_config directly.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230517102807.2181589-5-dmitry.baryshkov@linaro.org