Trying to get RTT working on an A53, and I need to configure the MMU to not cache the rtt buffer(s) (and I guess I want to align them to match up with an MMU block as well..). However, rtt_target allocates them with the rtt_init macro:
```
        $field[$number].init(name, mode, {
            static mut _RTT_CHANNEL_BUFFER: MaybeUninit<[u8; $size]> = MaybeUninit::uninit();
            _RTT_CHANNEL_BUFFER.as_mut_ptr()
        });
```
Is there a way to achieve this without rewriting rtt_target?