Generate LiteX SPI Flash with underlying memory
Generate LiteX SPI Flash with underlying memory

06bf6560228675483f60427ca28a9a228d08f199 in Renode
changed the way Micron MT25Q flash works - it has now
a backend memory that allows for direct code execution
(XIP feature).

Adapting to this change requires generating a new
`flash_mem` memory region and modifying binary-loading
instructions to target this memory.

litex-hub/litex-renode