arm64: dts: renesas: Add mmc aliases into board dts files

arm64: dts: renesas: Add mmc aliases into board dts files

After the commit 7320915c8861 ("mmc: Set PROBE_PREFER_ASYNCHRONOUS
for drivers that existed in v4.14"), the order of /dev/mmcblkN
was not fixed in some SoCs which have multiple sdhi controllers.
So, we were hard to use an sdhi device as rootfs by using
the kernel parameter like "root=/dev/mmcblkNpM".

According to the discussion on a mainling list [1], we can add
mmc aliases to fix the issue. So, add such aliases into Renesas
arm64 board dts files. Notes that mmc0 is an eMMC channel if
available.

[1]
https://lore.kernel.org/linux-arm-kernel/CAPDyKFptyEQNJu8cqzMt2WRFZcwEdjDiytMBp96nkoZyprTgmA@mail.gmail.com/

Fixes: 7320915c8861 ("mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.14")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1614596786-22326-1-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>