The rpi3b device tree specifies 1G of RAM in the memory node, but maps
the highest 16M of RAM's physical address range for peripheral use.

When support for device tree probing was first added for the rpi3b
in e8fab18835a1 ("ARM: rpi: switch to DT probe and multi-image build"),
it had a memory { } node overriding the kernel node size with 0, so the
size is computed later correctly.

1dc748b3b202 ("dts: update to v5.1-rc1") came and renamed the upstream
memory { } node to memory@0. So instead of overriding the old, we
now created a second dummy along with the broken node.
barebox did only parse the dummy, so it continued to limp along.

8226f7f90973 ("of: base: parse all available memory nodes") started
considering both nodes and rendered barebox v2020.05.0 unable to start
up on the rpi3b because of the conflict between RAM range and peripherals
like the bcm2835_mbox caused by parsing the broken memory node.

At least one board also was broken for the same reason[1], so a more
robust approach is in order. For nodes that lack a phandle, the
&{/path} syntax can be used instead. This has the benefit that should
the path disappear in future, a compile failure would result.

[1] 0d26ce1c11a1 ("ARM: Phytec phyFLEX i.MX6: delete wrong memory node")

Fixes: 1dc748b3b202 ("dts: update to v5.1-rc1")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>