drm/bridge: anx7625: register content protect property

Set the `support_hdcp` bit to enable the connector to register content
protection during initialization.

Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Fei Shao <fshao@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250812082135.3351172-3-fshao@chromium.org