Hi
SPI Flash is not memory mapped so it doesn't fit into the Kinetis address space. It is addressed by defining pages and offsets in the pages, which is not related to memory mapping in normal use and so also doesn't have any chance of collisions.
It is however possible to virtually memory map it at the API layer - see this video showing this in the uTasker project: https://www.youtube.com/watch?v=Pe9A8qsefzQ&index=12&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q
It doesn't specifically discuss SPI Flash in the video but the technique is the same and you can in fact see SPi Flash in the diagrams.
The open source uTasker project on GitHub includes support for about 5 different SPI memory manufacturers on most Kinetis parts, including storage display allowing it to be accessed in a virtual memory mapped environment (for file system use, for example) and testing using the same commands shown in the video. It also allows the Kinetis parts, SPI and these SPI Flash devices to be simulated for simplified development and debugging.
Regards
Mark
