arm64: dts: rockchip: Enable eMMC HS200 mode on Radxa E20C

eMMC HS200 mode (1.8V I/O) is supported by the MMC host controller on
RK3528 and works with the optional on-board eMMC module on Radxa E20C.

Be explicit about HS200 support in the device tree for Radxa E20C.

Fixes: 3a01b5f ("arm64: dts: rockchip: Enable onboard eMMC on Radxa E20C")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Link: https://lore.kernel.org/r/20250621165832.2226160-1-jonas@kwiboo.se
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Author: Kwiboo

arch/arm64/boot/dts/rockchip/rk3528-radxa-e20c.dts

@@ -283,6 +283,7 @@
 &sdhci {
 	bus-width = <8>;
 	cap-mmc-highspeed;
+	mmc-hs200-1_8v;
 	no-sd;
 	no-sdio;
 	non-removable;