ARM: dts: at91: sama5d27_som1_ek: add mmc capabilities for SDMMC0

Add mmc capabilities for SDMMC0 for this board.
With this enabled, eMMC connected card is detected as:

mmc0: new DDR MMC card at address 0001
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lore.kernel.org/r/1565252928-28994-2-git-send-email-eugen.hristev@microchip.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

arch/arm/boot/dts/at91-sama5d27_som1_ek.dts

@@ -53,6 +53,7 @@ usb2: ehci@500000 {
 
 		sdmmc0: sdio-host@a0000000 {
 			bus-width = <8>;
+			mmc-ddr-3_3v;
 			pinctrl-names = "default";
 			pinctrl-0 = <&pinctrl_sdmmc0_default>;
 			status = "okay";