spi_flash_mmap() function

Map region of flash memory into data or instruction address space This function allocates sufficient number of 64kB MMU pages and configures them to map the requested region of flash memory into the address space. It may reuse MMU pages which already provide the required mapping. As with any allocator, if mmap/munmap are heavily used then the address space may become fragmented. To troubleshoot issues with page allocation, use spi_flash_mmap_dump() function.