By default, HBR2 (5.4G) is the max link rate be supported. This patch
uses the actual limit specified by DT and removes the artificial
limitation to 5.4 Gbps. Supporting HBR3 is a consequence of that.

Changes in v2:
-- add max link rate from dtsi

Changes in v3:
-- parser max_data_lanes and max_dp_link_rate from dp_out endpoint

Changes in v4:
-- delete unnecessary pr_err

Changes in v5:
-- split parser function into different patch

Changes in v9:
-- revised commit test

Changes in v13:
-- repalced "properity" with "property"
Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/516097/
Link: https://lore.kernel.org/r/1672163103-31254-6-git-send-email-quic_khsieh@quicinc.comSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>