ARM: meson: keep HW order for MMC devices

Since Linux commmit [1], the order is fixed with aliases, in order to keep the
MMC device order, set it back to HW order in U-Boot dtsi files.

[1] ab547c4fb39f ("arm64: dts: amlogic: Assign a fixed index to mmc devices")

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>