arm64: dts: rockchip: Enable edp disaplay on kevin

Add edp panel and enable related nodes on kevin.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Mark Yao <mark.yao@rock-chips.com>
Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>