arm: dts: sunxi: Enumerate MMC2 as MMC1

Environment and fastboot MMC devices are configured based number
of mmc slots defined on particular board in sunxi platform.

If number of slots are not more than 1, it assigns 0 which usually mmc
device on SD slot. With DM_MMC it is detected as 0 since mmc0 node always
be an mmc device.

If number of slots are more than 1, it assigns 1 which assumes 0 is mmc
device and 1 is emmc device. But with DM_MMC there is chance of detecting
emmc as device 2 since mmc1 is SDIO as per devicetree definition.

So override mmc2 to mmc1 in sunxi dtsi, this will eventually detect mmc2
as mmc 1 device even if the board dts has mmc0, mmc1, mmc2.

Some platforms like A20 has mmc0...mmc3, but there is no usecases now for
enabling all mmc controllers in any of A20 board dts files.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

arch/arm/dts/sunxi-u-boot.dtsi

@@ -1,6 +1,10 @@
 #include <config.h>
 
 / {
+	aliases {
+		mmc1 = &mmc2;
+	};
+
 	binman {
 		filename = "u-boot-sunxi-with-spl.bin";
 		pad-byte = <0xff>;