riscv: dts: AE250 support sd High-Speed mode

Enable High-Speed mode with cap-sd-highspeed in dts.
Signed-off-by: NRick Chen <rick@andestech.com>
Signed-off-by: NRick Chen <rickchen36@gmail.com>

arch/riscv/dts/ae250.dts

@@ -74,6 +74,7 @@
 		fifo-depth = <0x10>;
 		reg = <0xf0e00000 0x1000>;
 		interrupts = <17 4>;
+		cap-sd-highspeed;
 	};
 
 	spi: spi@f0b00000 {