drm/i915/dsb: Plumb the whole atomic state into intel_dsb_prepare()

The DSB code will need to examine both the old and new crtc
states. Pass in the whole atomic state so we can dig up
what we need.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240611133344.30673-7-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>