arm64: dts: rockchip: remove redundant max-link-speed from nanopi-r4s

arm64: dts: rockchip: remove redundant max-link-speed from nanopi-r4s

This is already the default in rk3399-base.dtsi, remove redundant
declaration from rk3399-nanopi-r4s.dtsi.

Fixes: db792e9adbf8 ("rockchip: rk3399: Add support for FriendlyARM NanoPi R4S")
Cc: stable@vger.kernel.org
Reported-by: Dragan Simic <dsimic@manjaro.org>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Signed-off-by: Geraldo Nascimento <geraldogabriel@gmail.com>
Acked-by: Shawn Lin <shawn.lin@rock-chips.com>
Link: https://patch.msgid.link/6694456a735844177c897581f785cc00c064c7d1.1763415706.git.geraldogabriel@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>