arm64: dts: rockchip: add R69 XR821 TV box

Rockchip RK3518A (RK3528 family), quad Cortex-A53, Mali-450, 2GB DDR4, 16GB
eMMC, microSD, 10/100 Ethernet on the integrated PHY, AIC8800D80 SDIO Wi-Fi with
UART Bluetooth, USB2, USB3, HDMI, AV jack and an IR receiver.

The vendor ships no source for this board, only a DTB in its boot partition. That
tree's compatible names rk3528-evb1-ddr4-v10, and comparing the two confirms the
lineage - they share 581 of about 600 nodes - so this includes the reference board
and overrides what differs rather than carrying a decompiled tree.

Relative to the box's own factory tree the changes are:

  compatible         prepend the board name, so the tree identifies this box and
                     not the reference design; append rockchip,rk3528a, as rkmpp
                     has no rk3518 entry and cannot reach the VPU without it
  model              name the box, keeping the vendor string
  serial@ff9f0000    status okay + uart0m0_xfer pinctrl, for the ttyS0 console
  fiq-debugger       disabled; it owns ff9f0000 otherwise
  uart2              bluetooth serdev node, aicsemi,aic8800-bt
  pwm@ffa90030       remote_support_psci 0 -> 1, so the remote wakes the box
  gpu@ff700000       clocks/clock-names/interrupt-names in mainline lima form
  watchdog@ffac0000  status okay, for systemd's RuntimeWatchdogSec
  leds               power/standby labels, correct polarity, retain-state-*
  chosen             dropped; u-boot supplies bootargs, and the vendor string
                     names ttyFIQ0

Everything else follows from the reference board. Verified by compiling this file
and comparing it against the factory blob: the trees are content-identical, and
the result boots on the hardware.

Named for the PCB silkscreen, XR821_V1.1: "R69" alone is overloaded - Armbian
already ships sunvell-r69 for an unrelated Allwinner box - and these boxes vary
between production runs.

Signed-off-by: Artem Butusov <art.sormy@gmail.com>

Author: sormy

arch/arm64/boot/dts/rockchip/Makefile

@@ -96,6 +96,7 @@ dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire-excavator.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399-sapphire-excavator-edp-avb.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3399pro-rock-pi-n10.dtb
+dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3518-r69-xr821.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3528-armsom-sige1.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3528-demo1-lp4-v10.dtb
 dtb-$(CONFIG_ARCH_ROCKCHIP) += rk3528-demo4-ddr4-v10.dtb