The eDP BDB block has gained yet another max link rate field.
Let's parse it and consult it during the source rate filtering.

v2: *20 instead of *2 to get the correct units (Jani)
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220602205723.11341-1-ville.syrjala@linux.intel.com