Fixes for 5.16-rc2:
 - Fix an accounting problem where unaligned inline data reads can run
   off the end of the read iomap iterator.  iomap has historically
   required that inline data mappings only exist at the end of a file,
   though this wasn't documented anywhere.
 - Document iomap_read_inline_data and change its return type to be
   appropriate for the information that it's actually returning.