Fixes#435
`LDR x1, =__top_of_ram` already loads the top of RAM, so the `LDR x1, [x1]`
that followed read whatever sat at that address and left
`_tx_initialize_unused_memory` holding garbage.
Dropped that instruction from the 13 non-SMP GNU Cortex-A ports, the ARMv8-A
source they are generated from, and the two Cortex-A35 module examples. The SMP
GNU ports already had the correct form, and the Arm Compiler ports are
unaffected -- their symbol really does need the dereference.
`scripts/check_ports.sh` passes and the `gnu` CI job build-verifies the AArch64
ports. Not run on hardware.
Assisted-by: Copilot (Opus 5) <noreply@github.com>
Frédéric Desbiens
5d235a534c