arm64: dts: sun50i: Add support for A64 OLinuXino (with eMMC)

arm64: dts: sun50i: Add support for A64 OLinuXino (with eMMC)

A64 OLinuXino board from Olimex has three variants with onboard eMMC:
A64-OLinuXino-1Ge16GW, A64-OLinuXino-1Ge4GW and A64-OLinuXino-2Ge8G-IND. In
addition, there are two variants without eMMC. One without eMMC and one with SPI
flash. This suggests the need for separate device tree for the three eMMC
variants.

The Linux kernel upstream has chosen to create and use a separate device tree
for the eMMC variants instead of adding eMMC support existing device tree. These
changes to Linux kernel are queued for Linux 5.4.

commit <02bb66b347ff8115f53948f86b884e008ba385b9> ("arm64: dts:
allwinner: a64: Add A64 OlinuXino board (with eMMC)")

This patch has been tested on A64-OLinuXino-1Ge16GW and is based on Linux
device-tree and a64-olinuxino_defconfig.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
[jagan: updated linux-next commit details]
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>