board: rockchip: Add Xunlong Orange Pi 5 Plus

Xunlong Orange Pi 5 Plus is a single-board computer based on the
Rockchip RK3588 SoC. The board provides abundant interfaces, including
two HDMI output ports, one HDMI input port, two 2.5G Ethernet ports,
M.2 M-Key slot, M.2 E-Key slot, two USB 3.0, two USB 2.0, and two Type-C.

Features tested on a Orange Pi 5 Plus 4GB v1.2:
- SD-card boot
- eMMC boot
- SPI Flash boot
- PCIe/NVMe
- USB 2.0 host
- Ethernet

Device tree is imported from linux v6.7-rockchip-dts64-1 tag.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/doc/board/rockchip/rockchip.rst b/doc/board/rockchip/rockchip.rst
index a4b69b3..ffbebd0 100644
--- a/doc/board/rockchip/rockchip.rst
+++ b/doc/board/rockchip/rockchip.rst
@@ -119,6 +119,7 @@
      - Radxa ROCK 5A (rock5a-rk3588s)
      - Radxa ROCK 5B (rock5b-rk3588)
      - Xunlong Orange Pi 5 (orangepi-5-rk3588s)
+     - Xunlong Orange Pi 5 Plus (orangepi-5-plus-rk3588)
 
 * rv1108
      - Rockchip Evb-rv1108 (evb-rv1108)