drm/i915/mtl: Add DP rates

Add DP rates for Meteorlake.

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230413212443.1504245-2-radhakrishna.sripada@intel.com