drm/i915/display: Add support for pack and unpack

drm/i915/display: Add support for pack and unpack

Add support of pack and unpack for target_rr_divider.

--v2:
- Set Target Refresh Rate Divider bit when related
AS SDP bit is set (Ankit).

--v3:
- target_rr_divider is bools so set accordingly (Ankit).
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240610072203.24956-7-mitulkumar.ajitkumar.golani@intel.com