ARM: tegra: Restore DT ABI on Tegra124 Chromebooks

Commit 48299769 ("ARM: tegra: Fix unit_address_vs_reg DTC warnings
for /memory") inadventently broke device tree ABI by adding a unit-
address to the "/memory" node because the device tree compiler flagged
the missing unit-address as a warning.

Tegra124 Chromebooks (a.k.a. Nyan) use a bootloader that relies on the
full name of the memory node in device tree being exactly "/memory". It
can be argued whether this was a good decision or not, and some other
bootloaders (such as U-Boot) do accept a unit-address in the name of the
node, but the device tree is an ABI and we can't break existing setups
just because the device tree compiler considers it bad practice to omit
the unit-address nowadays.

This partially reverts the offending commit and restores device tree ABI
compatibility.

Fixes: 48299769 ("ARM: tegra: Fix unit_address_vs_reg DTC warnings for /memory")
Reported-by: Tristan Bastian <tristan-c.bastian@gmx.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Tested-by: Tristan Bastian <tristan-c.bastian@gmx.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>