rockchip: rk3568: Add support for FriendlyARM NanoPi R5C

FriendlyARM NanoPi R5C is an open-sourced mini IoT gateway device.

Specification:
- Rockchip RK3568
- 1/4GB LPDDR4X RAM
- 8/32GB eMMC
- SD card slot
- M.2 Connector
- 2x USB 3.0 Port
- 2x 2500 Base-T (PCIe, r8125)
- HDMI 2.0
- MIPI DSI/CSI
- USB Type C 5V

The device tree is taken from kernel v6.4-rc1.

Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Tianling Shen <cnsztl@gmail.com>
diff --git a/board/rockchip/evb_rk3568/MAINTAINERS b/board/rockchip/evb_rk3568/MAINTAINERS
index 9222682..a8ed250 100644
--- a/board/rockchip/evb_rk3568/MAINTAINERS
+++ b/board/rockchip/evb_rk3568/MAINTAINERS
@@ -7,6 +7,13 @@
 F:	arch/arm/dts/rk3568-evb-boot.dtsi
 F:	arch/arm/dts/rk3568-evb.dts
 
+NANOPI-R5C
+M:      Tianling Shen <cnsztl@gmail.com>
+S:      Maintained
+F:      configs/nanopi-r5c-rk3568_defconfig
+F:      arch/arm/dts/rk3568-nanopi-r5c.dts
+F:      arch/arm/dts/rk3568-nanopi-r5c-u-boot.dtsi
+
 NANOPI-R5S
 M:      Tianling Shen <cnsztl@gmail.com>
 S:      Maintained