IMFS bytes per block configuration question

[Joel Sherrill]

Hi

I accidentally set CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
to 1024 which is not supported. Only <= 512 is.

The code and imfs.h comments on maximum filesize based
on various block sizes are consistent.

I have two questions

+ It seems like this could be an compile time check by
   confdefs.h rather than a silent limiting to 512 at
   run-time. Thoughts?

+ I don't see any documentation on this. If I am
   correct, this needs to be added. Please confirm me
   on this?

Thanks in advance.

--joel