Nios II Gen2 core error

I see now, yes the message is quite explicit telling you what your problem is:

/*
 * Convert a pointer to a block of cached memory into a block of uncached memory.
 * Return a pointer that should be used to access the uncached memory.
 *
 * This routine was created for Nios II Gen1 cores which allow mixing cacheable and
 * uncachable data in the same data cache line. So, they could take any memory region
 * and make it uncached. However, Nios II Gen2 cores don't support mixing cacheable
 * and uncachable data in the same data cache line so require the memory region to
 * be aligned to a cache line boundary and must be an integer number of cache line
 * bytes in size. So, software on a Nios II Gen2 core shouldn't really be using this
 * function so it fails with a link error.
 */
volatile void* 
alt_remap_uncached(void* ptr, alt_u32 len)
{
  /* Generate a link time error, should this function ever be called. */
  ALT_LINK_ERROR("alt_remap_uncached() is not available because Nios II Gen2 cores with data caches don't support mixing cacheable and uncacheable data on the same line.");
  return NULL;
}