arm64: dts: rockchip: rk3308: Add Radxa ROCK Pi S support

Add Radxa ROCK 3 Model A support. sync rk3308-rock-pi-s.dts from
Linux 6.2.0-rc7.

ROCK Pi S is RK3308 based SBC from radxa.com. ROCK Pi S has a,
- 256MB/512MB DDR3 RAM
- SD, NAND flash (optional on board 1/2/4/8Gb)
- 100MB ethernet, PoE (optional)
- Onboard 802.11 b/g/n wifi + Bluetooth 4.0 Module
- USB2.0 Type-A HOST x1
- USB3.0 Type-C OTG x1
- 26-pin expansion header
- USB Type-C DC 5V Power Supply

Linux commit commit for the same,
<2e04c25b1320> ("arm64: dts: rockchip: add ROCK Pi S DTS support")

Signed-off-by: Akash Gajjar <gajjar04akash@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/board/rockchip/evb_rk3308/MAINTAINERS b/board/rockchip/evb_rk3308/MAINTAINERS
index 0af119a..fe2c5f0 100644
--- a/board/rockchip/evb_rk3308/MAINTAINERS
+++ b/board/rockchip/evb_rk3308/MAINTAINERS
@@ -4,3 +4,10 @@
 F:      board/rockchip/evb_rk3308
 F:      include/configs/evb_rk3308.h
 F:      configs/evb-rk3308_defconfig
+
+ROCK-PI-S
+M:      Akash Gajjar <gajjar04akash@gmail.com>
+S:      Maintained
+F:      configs/rock-pi-s-rk3308_defconfig
+F:      arch/arm/dts/rk3308-rock-pi-s.dts
+F:      arch/arm/dts/rk3308-rock-pi-s-u-boot.dtsi