arm64: dts: ls1028a: enable DP node for RDB/QDS boards

commit 734ffe43bcdbea9c26087567fbe2846244b030e9 from
https://source.codeaurora.org/external/imx/linux-imx



This patch enables HDP PHY Controller related nodes on RDB/QDS boards.

[Leo: Binding not upstream]

Signed-off-by: Alison Wang <alison.wang@nxp.com>
Signed-off-by: Wen He <wen.he_1@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>