arm64: dts: rockchip: Assign a fixed index to mmc devices on rk3399 boards.

[ Upstream commit 0011c6d182 ]

Recently introduced async probe on mmc devices can shuffle block IDs.
Pin them to fixed values to ease booting in environments where UUIDs
are not practical. Use newly introduced aliases for mmcblk devices from [1].

[1]
https://patchwork.kernel.org/patch/11747669/

Signed-off-by: Markus Reichl <m.reichl@fivetechno.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20201104162356.1251-1-m.reichl@fivetechno.de
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/arm64/boot/dts/rockchip/rk3399.dtsi

@@ -29,6 +29,9 @@
 		i2c6 = &i2c6;
 		i2c7 = &i2c7;
 		i2c8 = &i2c8;
+		mmc0 = &sdio0;
+		mmc1 = &sdmmc;
+		mmc2 = &sdhci;
 		serial0 = &uart0;
 		serial1 = &uart1;
 		serial2 = &uart2;