Add "big" and "huge" types to mke2fs.conf

Add "big" and "huge" types to mke2fs.conf

mke2fs attempts to use the "big" and "huge" types, and now that mke2fs
will complain if there are file system types which are undefined,
let's add definitions for them.

Thanks to Richard Jones for reporting this problem.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>