arm64: dts: rockchip: remove unsupported property from sdmmc2 for rock-3a

'supports-sdio' is not part of the DT binding
and not supported by the Linux driver.
Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
Link: https://lore.kernel.org/r/20221219101052.7899-1-amadeus@jmu.edu.cnSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3568-rock-3a.dts

@@ -737,7 +737,6 @@ &sdmmc0 {
 };
 
 &sdmmc2 {
-	supports-sdio;
 	bus-width = <4>;
 	disable-wp;
 	cap-sd-highspeed;