arm64: dts: rockchip: configure eth pad driver strength for orangepi r1 plus lts

The default strength is not enough to provide stable connection
under 3.3v LDO voltage.

Fixes: 387b3bba

 ("arm64: dts: rockchip: Add Xunlong OrangePi R1 Plus LTS")
Cc: stable@vger.kernel.org # 6.6+
Signed-off-by: Tianling Shen <cnsztl@gmail.com>
Link: https://lore.kernel.org/r/20231216040723.17864-1-cnsztl@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>