arm64: dts: rockchip: Lower sd speed on rk3566-soquartz

Just like the Quartz64 Model B the previously stated speed of sdr-104
in soquartz is too high for the hardware to reliably communicate with
some fast SD cards.
Especially on some carrierboards.

Lower this to sd-uhs-sdr50 to fix this.

Fixes: 5859b5a9 ("arm64: dts: rockchip: add SoQuartz CM4IO dts")
Signed-off-by: Dan Johansen <strit@manjaro.org>
Acked-by: Peter Geis <pgwipeout@gmail.com>
Link: https://lore.kernel.org/r/20230304164135.28430-1-strit@manjaro.org


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