board: rockchip: Add Xunlong Orange Pi 5 Ultra

board: rockchip: Add Xunlong Orange Pi 5 Ultra

The Orange Pi 5 Ultra is another board in the Orange Pi 5 family.

Orange Pi 5 Ultra uses Rockchip RK3588,
a new generation of octa-core 64-bit ARM processor,
which includes quad-core A76 and quad-core A55.

Features tested on a Orange Pi 5 Ultra 16GB:
- SD-card boot
- eMMC boot

ROCKCHIP_TPL:
https://github.com/rockchip-linux/rkbin/tree/master/bin/rk35/rk3588_ddr_lp4_2112MHz_lp5_2400MHz_v1.18.bin

BL31:
https://github.com/rockchip-linux/rkbin/tree/master/bin/rk35/rk3588_bl31_v1.48.elf

Signed-off-by: Niu Zhihong <zhihong@nzhnb.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>