sunxi: dts: H616: Drop reserved-memory node

Trusted Firmware now adds the /reserved-memory subnode to the DT at
runtime[1], putting in the right values.

Drop our hard-coded version, as this might clash with the actual values
(which have also changed), and rely on TF-A to add the node.

[1] https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/7770



Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>