topic: Use distro_boot for topic-miami boards

topic: Use distro_boot for topic-miami boards

Adjust configuration and devicetree so the topic-miami board actually
boots.

Replace the custom scripting and just use distro_boot. Override the
standard zynq routines.

The board attempts to boot from SD card first, and falls back to booting
UBIFS from the QSPI NOR flash.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Link: https://lore.kernel.org/r/20250312153741.24007-2-mike.looijmans@topic.nl
Signed-off-by: Michal Simek <michal.simek@amd.com>